received 6 calls to my cell phone within 2 hours

Fax machine from Plano, Texas keeps calling my cell phone

I receive two calls every morning from this phone number!

Receiving fax transmission to my business cell phone (8 attempts in the past 12 hours (Sunday evening to Monday morning) - one online search indicated Plano, TX, as point of origin registered with MCI Worldcom Communications, Inc. as service provider

I actually just called Onstar to have my doors unlocked and this was the phone number they called me back from.  I googled this number because I was curious where the call center was located.