Phone does weird

My american phone is acting weird. Someone tried to call me last night, but it turned all the calls down and I received an sms that I didn't have enough credit on my phone. So I spend 45min to look for a place where I could get a prepaid card for my Verizon phone and it turned out that in the whole of NYC you can only get that at the verizon stores, which were of course all closed. Now I asked someone to call me and it works again, so I don't have a clue what's going on. If you try to call me and don't get through, try again, write me an sms or an email. Sorry for any inconvenience...