I keep getting calls from this number over the course of 2 weeks. Sometimes, the caller leaves a voice mail, however it's a robot and claims to be from T-Mobile.
I have gotten numerous calls from this number, sometimes three in one day. Today is the first time I picked up. The recorded message said they were T-Mobile and my bill is past due. As far as my records show I am up to date. On the few occasions I have been late T-Mobile sends a text.