SMB5100 Stops Returning Serial Output

My SMB5100 stops sending Serial Data to the NSS port after about 30 minutes.

I have my module:

Connect to the network (happens automatically when arduino starts)

wait

Check for new messages

wait

If New message, go to last message

wait

Get the phone number from the last message

wait

Txt the phone number

wait

Send reset command to Cell chip

wait

Connect to network and start the whole thing over again.

After about 20 iterations, i stop receiving anything in my serial port from the SM5100.

Has anyone run into this problem? Any thoughts?