I send to Moens in Part Deux and I've never got a GPS from him either. It certainly makes it difficult to know if the turn arrived or not.
I do know that Moens, and Ruff who follows on from him, are pretty fast turnaround players so when the turn doesn't arrive with me a couple of days after it was sent to Joe then I think its logical to assume that it never reached Moens.
I think that it is a reasonable request to ask that, at least for the next few turns, both Joe and Moens post GPS on this thread ... this will hopefully show if there is a problem with Joe sending to Moens.