I need to use a string list to update multiple records, but only a single record is updating.

I have this to deserialize my incomng json:

public class person {
    public String serviceID;
    public String responseStatus;
    public cls_equipmentList[] equipmentList;
}
class cls_equipmentList {
    public String action;
    public String receiverID;
    public String location;
    public String smartCardID;
    public String leaseInd;
}

I can see my data with:

        System.debug('DEBUG 3 ======== obj.equipmentList: ' + obj.equipmentList);

Which returns:

(cls_equipmentList:[
action=ADD, leaseInd=false, location=C, receiverID=R1270000274, smartCardID=S1270000274
],
cls_equipmentList:[
action=ADD, leaseInd=false, location=C, receiverID=R1270000264, smartCardID=S1270000264
])


Then I want to update each record in the equipmentList based on receiverID, but only the first record is updating.

I tired this:

    if(obj.equipmentList[0].receiverID != null){
        List<Equipment__c> allEQ = [SELECT Id, Name FROM Equipment__c WHERE Name = :obj.equipmentList[0].receiverID ];
        for (Equipment__C currentEQ : allEQ) {
            currentEQ.Action__c = 'Active';
        }
        update allEQ;
    }

All help is appreciated.