New Phone from Craigslist is Blacklisted

I just bought a new HTC One M8 from a Craigslist girl last night. She said that there she had problems with her original phone and ordered this new one but then was able to fix the original. She was asking $300 but I got it for $225. I know, alarms should've been going off but it was a long day etc. I checked the IMEI at https://imeidata.net/ this morning and it says that T Mobile has blacklisted it for Finance. Curiously, https://swappa.com/esn does NOT show my phone as being blacklisted.

What to do now? Which website can I trust? It is a T Mobile phone so should I contact them? I am going to use it with MetroPCS.

 

just spoke with TM and they say that "as of now" the phone is not blocked but it could be blocked in the future if the former owner does not pay for it. I didn't tell them that I was the new owner, just that I was considering buying it.

 

The seller is not responding to my texts. TM Customer Care said that they would try contacting her and remind her that she needs to either send back the "non-functioning" phone or pay $600 for the new one, which she sold to me (for $225).

I appreciate the advice re police report but what would that accomplish? It doesn't seem that any laws have been broken. I could try taking her to small claims court...