I received multiple calls from this fax machine (1-610-650-2300, got this number by *69) very early in morning and after researching it, I found out that it is Quest Diagnostics and also found this website.
You will find toll free numbers for many states. I called the toll free number, they asked for my phone number and the number the call was coming from and was assured that my number would be removed.
I get repeated calls in the middle of the night around 3 a.m. Tried calling it back and was put on hold. Spoke with Darlene. Said the same as others that it was a fax line. They took the info and blocked my number from being called.