Cannot make nor receive phone calls

I asked for a new number a few weeks ago, and I don't remember if I checked it with an incoming call, my bad. But now we do not receive calls, says number not accepting calls; and cannot call out - all we get is a fast beep like a busy signal. Chatted with two agents, last just said to sign up for the $75 care plan. It's bad enough paying $300 a month, can't add another $75.