Help with a locked Note 4

I purchased a T-mobile Note 4 via OfferUp and I didn't check phone properly. Purchasing in a parking lot, I made sure it powered up and checked to make sure it was a Note 4, but guy looked honorable. I KNOW BIG MISTAKE. Got home and found a lens on back camera cracked. And, didn't know to put my T-mobile SIM card in to check before purchasing. Called to change my T-mobile to put on my account and the IMEI# was bad & T-mobile had it locked, T-mobile said that the phone was never paid for and therefor locked. Ordered a Net10 SIM and a months service. When I got Net10 SIM, went to my account to activate. Wouldn't work! Took to a boost store and guy checked and said it wouldn't unlock. Do I have any options or do I loose my 0 and call it a monster learning experience. Its running on 5.0.1 Lollipop!
Any help would be greatly appreciated.
Thanks,
John
johnwnusz@gmail.com