Problems with digital telephone?

[boilerette72]

We recently got digital telephone with our cable. The digital telephone/modem unit is NOT hooked to our wall telephone jack. The digital telephone is hooked DIRECTLY to our telephone/modem. The old wall telephone still works! The number was supposed to be ported over from verizon to cox. When I call out from either the digital telephone, or the old telephone hooked to the wall jack, the same number shows up on caller ID. When I try to call my home, it only rings on the OLD telephone jack. What's going on? Cox is stumped.