Dead letter queue service stops picking up messages

Hi
I have a custom dead letter queue service to pick up messages from DLQ. This service picks up failed message from DLQ and tries to resend to a different end point. If the new endpoint doesn't work, it rolls back transaction. This works great. Here is the code.
{
    [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single,
        ConcurrencyMode = ConcurrencyMode.Single,
        AddressFilterMode = AddressFilterMode.Any)]
    public class FDPDLQService : IFDService
    {
        FDPManager _fdpManager = new FDPManager();
        [OperationBehavior(TransactionScopeRequired = true, TransactionAutoComplete = true)]
        public void ProcessFDMessage(FDMessage message)
        {
            //System.Diagnostics.Debugger.Launch();
            try
            {
                MsmqMessageProperty mqProp =
                    OperationContext.Current.IncomingMessageProperties[MsmqMessageProperty.Name] as MsmqMessageProperty;
                // if message log required, and configured, log the incoming message
                try
                {
                ChannelFactory factory = new ChannelFactory("IFDPRouter_EP");
                IFDPRouter proxy = factory.CreateChannel();
                string ep = proxy.GetNextEPForGivenEP(OperationContext.Current.IncomingMessageHeaders.To.ToString());
                if (ep == null || ep == string.Empty)
                {
                    throw new EndpointNotFoundException(Common.Constants.FDP_NOT_FOUND_EXCEPTION_MESSAGE);
                }
                // Process message with next end point available
                _fdpManager.ProcessFDMessage(message, ep);
            }
            catch (EndpointNotFoundException enfe)
            {
                ExceptionManager.HandleException(enfe);
                Transaction.Current.Rollback();
                //throw;
            }
            catch (Exception ex)
            {
                ExceptionManager.HandleException(ex);
                Transaction.Current.Rollback();
                //throw;
            }
        }
    }
}
Below is config entries.


   
       
           
                          receiveTimeout="00:10:00" sendTimeout="00:01:00"  deadLetterQueue="Custom" customDeadLetterQueue ="net.msmq://localhost/private/FDPDLQ"
            durable="true" exactlyOnce="true" maxReceivedMessageSize="65536"
            maxRetryCycles="2" receiveErrorHandling="Fault" receiveRetryCount="5"
            retryCycleDelay="00:30:00" timeToLive="00:01:00" useSourceJournal="false"
            useMsmqTracing="false" queueTransferProtocol="Native" maxBufferPoolSize="524288"
            useActiveDirectory="false">
                                    maxBytesPerRead="4096" maxNameTableCharCount="16384" />
               
                                        msmqProtectionLevel="Sign" msmqSecureHashAlgorithm="Sha1" />
                 
               
               
             
             
               
             
                                    receiveTimeout="00:10:00" sendTimeout="00:01:00"
                    durable="true" exactlyOnce="true" maxReceivedMessageSize="65536"
                    maxRetryCycles="2" receiveErrorHandling="Fault" receiveRetryCount="5"
                    retryCycleDelay="00:30:00" timeToLive="00:01:00" useSourceJournal="false"
                    useMsmqTracing="false" queueTransferProtocol="Native" maxBufferPoolSize="524288"
                    useActiveDirectory="false">
                                            maxBytesPerRead="4096" maxNameTableCharCount="16384" />
                   
                                                    msmqProtectionLevel="Sign" msmqSecureHashAlgorithm="Sha1" />
                       
                   
               
                                    receiveTimeout="00:10:00" sendTimeout="00:01:00" deadLetterQueue="System"
                    durable="true" exactlyOnce="true" maxReceivedMessageSize="65536"
                    maxRetryCycles="2" receiveErrorHandling="Fault" receiveRetryCount="5"
                    retryCycleDelay="00:30:00" timeToLive="1.00:00:00" useSourceJournal="false"
                    useMsmqTracing="false" queueTransferProtocol="Native" maxBufferPoolSize="524288"
                    useActiveDirectory="false">
                                            maxBytesPerRead="4096" maxNameTableCharCount="16384" />
                   
                                                    msmqProtectionLevel="Sign" msmqSecureHashAlgorithm="Sha1" />
                       
                   
               
           
           
               
           
       
     
       
         
           
         
       
     
     
       
                              contract="FDPServiceRef.IFDService"
                    bindingConfiguration="DefaultBinding">
       
     
       
                            binding="netMsmqBinding" bindingConfiguration="DLQServiceBinding"
                contract="FDPServiceRef.IFDService" name="FDService_EP" />
       
   

This works great.
But if all endpoints are not available for a long period of time, and if service rolls message back to the DLQ for a long period of time, after a certain period of time service stops picking up messages from DLQ. I am not sure which configuration is responsible for this. Can you guide me?
Regards
Jaimin Gandhi.