N.C.
I am no psychology expert, but it just sounds like he is exerting some independence for himself. See what happens if you just let him NOT talk to them as he chooses for awhile. He may also be frustrated about the fact that they are not there in person. With a 3 yr old, my guess is, this will pass. I would not make too much of a big deal about it or he will find it real fun to exert so much power over adults by being rude and non-communicative.