I had one of these hang up calls this morning and decided to call back and tell them to take me off their call list. A very odd thing happened when I tried twice. The number immediately morphed into another number with a 4 instead of the 1 indicating a long distance call, and the the phone company electronic voice told me to dial 1. It's really weird, I'd love to know what they're up to.
I have received phone calls from 413-785-5340, 413-785-5099. 413-785-5988 many many times during the day and night. Unknown name. Trying to check out who is calling, I find only that the provider is Verizon and the calls come from around Columbus St in Springfield, MA