I do not think I am doing a webservice call though. Here is my class. I left off the send emails method because it was too long. It just sends emails out based on the Contacts ID, which is not a webservice call.

public class NUBSCartController {

    public String oppid {get;set;}
    public String isConference {get;set;}
    public list<Integer> tableSkew {get;set;}
    public Event_Registration__c application {get;set;}
    public String sponserName {get;set;}
    public String sponserEmail {get;set;}
    
    public Opportunity opp {get;set;}
    public Student_Application__c app {get;set;}
    public Boolean showConfirm {get;set;}
    public Boolean showThankYou {get;set;}
    
    public String BillingFirst {get;set;}
    public String BillingLast {get;set;}
    public String BillingAddress {get;set;}
    public String BillingCity {get;set;}
    public String BillingState {get;set;}
    public String BillingCountry {get;set;}
    public String BillingPostcode {get;set;}
    
    public String CardType {get;set;}
    public String CardNumber {get;set;}
    public String CardMonth {get;set;}
    public String CardYear {get;set;}
    public String CardSecurity {get;set;}
    
    public list<SelectOption> CardTypeList {get;set;}
    public list<SelectOption> CardMonthList {get;set;}
    public list<SelectOption> CardYearList {get;set;}
    
    public list<OpportunityLineItem> oli {get;set;}
    
    public NUBSCartController() {
        oppid = ApexPages.currentPage().getParameters().get('oppId');
        isConference = ApexPages.currentPage().getParameters().get('isConference');
        opp = [SELECT o.Amount, o.name, o.contact__c, o.id FROM Opportunity o WHERE o.id =: oppid];
        if(isConference == 'true') {
            application = [SELECT name, id, hasPaid__c, Applicant_Name__c FROM Event_Registration__c WHERE Applicant_Name__c =: opp.contact__c AND name LIKE '%Conference%'];
            sponserName = 'Sabine Wimmer';
            sponserEmail= 'Sabine.Wimmer@mccombs.utexas.edu';
        }
        else if(isConference == 'false') {
            application = [SELECT name, id, hasPaid__c, Applicant_Name__c FROM Event_Registration__c WHERE Applicant_Name__c =: opp.contact__c AND name LIKE '%CareerServices%'];
            sponserName = 'Megan Fortson';
            sponserEmail = 'Megan.Fortson@mccombs.utexas.edu';
        }
        oli = [SELECT o.name, o.id, o.PricebookEntry.Product2.name, o.unitprice FROM OpportunityLineItem o WHERE o.OpportunityId =: opp.id]; 
        populatePicklists();
        showConfirm = false;
        showThankYou = false;
        tableSkew = new list<Integer>();
        tableSkew.add(1);
    }
    
    public void populatePicklists() {
        
        list<Schema.PicklistEntry> ple; // Declare variable
        
        /* Instansiate picklists */
        CardTypeList = new list<SelectOption>();
        CardMonthList = new list<SelectOption>();
        CardYearList = new list<SelectOption>();
        
        /* Get values from chargent card type and add to card type picklist */
        ple = Opportunity.ChargentSFA__Card_Type__c.getDescribe().getPicklistValues();
        for (Schema.PicklistEntry p:ple) {
            CardTypeList.add(new SelectOption(p.getValue(), p.getValue()));
        }
        
        /* Add values to expiration month picklist */
        CardMonthList.add(new SelectOption('01', '01'));
        CardMonthList.add(new SelectOption('02', '02'));
        CardMonthList.add(new SelectOption('03', '03'));
        CardMonthList.add(new SelectOption('04', '04'));
        CardMonthList.add(new SelectOption('05', '05'));
        CardMonthList.add(new SelectOption('06', '06'));
        CardMonthList.add(new SelectOption('07', '07'));
        CardMonthList.add(new SelectOption('08', '08'));
        CardMonthList.add(new SelectOption('09', '09'));
        CardMonthList.add(new SelectOption('10', '10'));
        CardMonthList.add(new SelectOption('11', '11'));
        CardMonthList.add(new SelectOption('12', '12'));
        
        /* Add 2014 + 50 more years to expiration year picklist */
        Integer startYear = System.TODAY().year();
        for (Integer i = 0; i < 50; i++) {
            CardYearList.add(new SelectOption(string.valueOf(startYear + i), string.valueOf(startYear + i)));
        }
    }
    
    public void preCharge() {
        
        showConfirm = true;
        
        assignVariables(); // Port over variables from page to opportunity fields
        
        update opp; // Save opportunity record
    }
    
    public void cancel() {
        showConfirm = false;
    }
    
    public PageReference printable() { 
        pageReference reRend = new PageReference('/apex/NUBSSummary?Oppid=' + opp.id);
        reRend.setRedirect(true);
        return reRend;
    }
    
    public void processPayment() {
       
       application.hasPaid__c = true;      
         
       Contact c = [SELECT name, id, email, firstName FROM Contact WHERE id in (select o.contact__c from opportunity o where o.id =: oppid)];
               
       ChargentSFA.TChargentOperations.TChargentResult result = ChargentSFA.TChargentOperations.ChargeOpportunity_Click(opp.Id);
        
        Opportunity opp2 = [SELECT Id, ChargentSFA__Balance_Due__c FROM Opportunity WHERE Id = :opp.Id];
        
        if (opp2.ChargentSFA__Balance_Due__c == 0) {       

            opp.StageName = 'Closed Won';
            
            update opp;
            
            showConfirm = false;
            showThankYou = true;            
            sendEmails(c);         
            list<ConProd_Bridge__c> cpbs = [SELECT name, id, Status__c, Remaining_Payment__c, Product__c, Contact__c FROM ConProd_Bridge__c 
                                       WHERE Product__r.pertains_To__c = 'NUBS2015' AND (Product__r.name LIKE '%Thursday, March 26, Opening Reception%' OR 
                                       Product__r.name LIKE '%Thursday, March 26, Dinner with Keynote Speaker%' OR Product__r.name LIKE '%Friday, March 27, Lunch at the Alumni Center%'
                                       OR Product__r.name LIKE '%Friday, March 27, Closing Dinner at the Rattle Inn%') AND Contact__c =: c.id];
                                       
            if(cpbs != null) {
                for(ConProd_Bridge__c cpb : cpbs) {
                    cpb.Remaining_Payment__c = 0;
                    cpb.Status__c = 'Paid';
                }
            }
            update cpbs;                           
            update application;
        } else {
            showConfirm = false;

            ApexPages.addMessage(new ApexPages.message(ApexPages.severity.ERROR, 'There was an error processing your payment. Make sure all fields are filled in correctly.'));
        }
        
    }
    
    public void assignVariables() {
        
        opp.ChargentSFA__Billing_First__c = BillingFirst;
        opp.ChargentSFA__Billing_Last__c = BillingLast;
        opp.ChargentSFA__Billing_Address__c = BillingAddress;
        opp.ChargentSFA__Billing_City__c = BillingCity;
        opp.ChargentSFA__Billing_State__c = BillingState;
        opp.ChargentSFA__Billing_Country__c = BillingCountry;
        opp.ChargentSFA__Billing_Postcode__c = BillingPostcode;
        
        opp.ChargentSFA__Card_Type__c = CardType;
        opp.ChargentSFA__Card_Number__c = CardNumber;
        opp.ChargentSFA__Card_Month__c = CardMonth;
        opp.ChargentSFA__Card_Year__c = CardYear;
        opp.ChargentSFA__Card_Security__c = CardSecurity;
        
        opp.ChargentSFA__Payment_Method__c = 'Credit Card';
    }
}