Just got ANOTHER call from them, they never leave a message, I called back the number and all I get is static. My guess is Verizon also but Verizon has successfully called me many times before from their own 800 number, not some sketchy, seemingly-local number that you can't call back. This is a business phone so when I see the local area code it could honestly be anyone and I only call back people who leave a message, but this has been a few days running now so hopefully it stops soon. I have paid my phone bill so that can't be the problem, maybe it's a solicitor. The govt do-not-call list simply doesn't work.
Hope this helps anyone who gets these calls in the future.