I've been using my BLU Studio 5.5 S for work, and instead of owning a separate work Phone I thought it would be good to use this phone because of it's dual SIM management. However, when I put the two SIM cards in, one from AT&T (my own provider) and one from Verizon (work provider). Only my SIM card is recognized and I can only receive calls from that service. Any idea what's going on here?