Who called from 6103379080

I have been getting at least one call daily for the last three days. Always about 20:00 MDT.
This is what I have found in my searches

(610) 337-9080
Type: Land Line
Provider: Verizon
Location: Philadelphia, PA

called two times to my cell Phone, No message was left. Caller ID said Unknown.

keeps calling my phone leaves no messages when you call the number back
keeps ringing.no idea what this is.

I received a call from this # today-I'm in the Midwest it was about 8pm here-anyone else have SPRINT/Nextel and their contract is expiring? I think they are trying to renew

I have had this number call me 2 times now. No message and I won't answer, because I don't know the number. And also I had Nextel/ Sprint and I just went to Verizon last week. I didn't know if they (nextel) are trying to keep my service and that is what the calls are for.