Who called from 3074592990

I've gotten at least 3 calls a week from this number for the past 3 months, despite my being on the national do not call list. I usually don't answer since they almost always call when I'm at work, but when I've tried to call back, I either get a busy signal, or a message saying "this mailbox is full". I'm getting pretty tired of this BS!

THIS IS THE NEW WAY FOR TELEMARKETERS TO GET AROUND THE DO NOT CALL LIST

For the last couple of days, I have been calls from this number endlessly.  They never leave a message.

Block your phone from receiving calls from numbers not in your phonebook. Has anyone contacted their own carrier to see if they can launch an investigation?

I keep getting a call from this number for days now.  When I answer the phone, they hang up.