phone gives a message saying file too large to send no matter what pic

my phone gives a message saying file too large to send no matter what picture i try to send. ive reset the phone, resetthe network, and nothing helps, its a brand new sim card in what is supposed to be a brand new leftover phone. ive done all the updates, tried ##brand#, tried ##72786#, and nothing fixes it. also sometimes if in an app like facebook or ebay and people try to call me it doesnt ring at all. and sometimes i dont receive picture texts or normal texts either. i have had it over to the boost store a couple times and the only thing the guy could say is that maybe the issue is due to the sprint/tmobile merger.