I was getting the fax calls too... 5 in about 15 minutes... I called the company that the fax line is affiliated with and spoke with a lady who said that she would make sure the issue was taken care of. The company is Athena health and the number to call is 800-981-5084.
I dialed the number back (Athena Health Fax Error Call Back) and got a voicemail explaining that if you are receiving a fax call, to leave a message and they will correct it.
They call many people, repeatedly (every 4-5 minutes), from their fax machine. The calls are coming from Athena Health fax. I called Athena Health three times, 800.981.5084, Option 3, and complained. They promised to take care of this. First time they said it would be taken care of immediately; the second time (a different person) I was told this would take a few hours, the third time (a different person) told me this should take 15-20 minutes to get resolved. I told them that a) each time I receive another call I will call them and complain; and b) I'm filing a compliant with FCC because mu phone is in the "Do not call" registry.