my s6 edge IMEI is blacklisted now, is there anything i can do myself or take it to..

hey guys, before i rooted my phone i messed it up and lost my imei and was stuck in a boot screen, i took it to a shop 30 mins from me and they charge me and they added a imei on my phone, the phone as been working for more than a month and it stop working yesterday and i check the imei on the tmobile site and it says it was blocked and no network would work under it. is i dont have a backup of the original imei but i have the box with the imei written on it, is there anything i can do, if not then i would just take it to the shop again and have them add a imei to it, let me know guys thanks!