Please hear my story and help with advice.
I purchased a brand new, unopened, T-Mobile branded S7 from Swappa last year. When I requested it to be unlocked, it was done by a kind person in the Social Media team; the unlock process wasn't straight forward at that time; he had to use something called an "Override tool" to do it. The Device Unlock app confirmed that it was indeed unlocked after that.
Then this February, the phone was turning itself off and restarted at unexpected times. So I sent it to Samsung for service under warranty. The phone came back, however it was SIM-locked. I contacted Samsung about this first and they bounced me to T-Mobile.
I've been requesting it to be unlocked again since then; but different members of the support team is saying that this IMEI wasn't present in their database and the only way they could unlock a device is if it is purchased from T-Mobile directly. I'm not sure if this is accurate. It was done the first time, why not again?
If that's the case, if I'm given a phone as gift by someone who no longer is around, how do I know where they bought it? What are my options here? Why is this so difficult? Please help.