I am looking for a little guidance on my REGEX statement for a Patter/Matcher Class that extracts a specific string from the body of a plain text email.

The desired match should be as follows:
REF#:xxxx 
where xxxx represents a 4 digit number

Here is a sample of the email body I am attempting to parse with a while loop using the matcher:

Wed Dec 10 10:46:59 2014: Request 68000 was acted upon.
Transaction: Ticket created by cashworth
       Queue: New Orders
     Subject: Service Disconnect Ticket: Test Account LLC
       Owner: Nobody
  Requestors: cashworth@somedomain.net
      Status: new


Requestor: Clay Ashworth <cashworth@somedomain.net>
CustomField.{Customer Number}:TES002

Service Items for Termination:

Ref#:0000
Product: Test Product
Quantity: 1
Total MRC: 0.00
Item Description: test product
Service Location(s):
Some Location Test

Last Date of Service: 2014-12-31 00:00:00

Below is a Code Sample of the Patter and Matcher portion of the Class. The intent being to find a match to the desired string 'REF#:xxxx', strip out only the number portion of the string and then do a SOQL query against a customer object ServiceLineItem__c. where the field Disconnect_Ticket__c can be updated with a variable derived earlier in the class (ticket) and then added to a list of SObjects for a bulk update.
 

//Pattern-Matcher to find ref numbers
        		Pattern RefP = Pattern.compile('REF#:[0-9]{4}');
        		
        		Matcher RefM = RefP.matcher(email.plaintextbody);     		
        		
        		//Loop through the matches	
        		while (RefM.find()) {
        			
	       			ref = RefM.group().right(4);
        			system.debug(ref);
        		
        		//Build list of Service Line Items with ref numbers and Lookup ref numbers and update with ticket number
	
					if(ref != null) {
        				ServiceLineItem__c sli = [select Id, CIS_Id__c from ServiceLineItem__c where CIS_Id__c = :ref limit 1];
        					if(sli != null) {
        						sli.Disconnect_Ticket__c = ticket;
        						sliList.add(sli);
        					}
        					
					}
					
        		}
        			
        	}

        		
        	//Update the Service Line Items with the disconnect ticket number
        	if(sliList != null) {
        			
        		update sliList;
        			
        	}

I am having difficulty getting the REGEX to match the desisred string and could use some assistance.

Thx