MessageSend - Asterisk 11.9.0 - GoIP

Hi, I have an SMS Gateway (Hybertone GoIP-1i) interfaced to my Astersik 11.9.0 server to send and receive SMS messages via Asterisk MessageSend. I am able to send and receive SMS messages via the GoIP. However, I am experiencing a problem: for some reason Asterisk seems to detect messages coming in that are not air bound messages sent to GoIP, it is a repeating message: sometimes none, sometimes only a few and sometimes thousands of them in a day. I have involved the GoIP manufacturer but they claim the GoIP is not at fault. I don’t know how to properly debug receiving SMS messages in Asterisk so see if the issue originates in the Asterisk server or not (sensing incoming messages). Comments or advise would be greatly appreciated.