To qualify for a SIM unlock.  The device must be a T-Mobile USA device, you must be a T-Mobile USA customer, and you must meet all of the SIM Unlock Policy requirements.  

SIM Unlock Policy | Unlock Your Mobile Wireless Device (t-mobile.com)

Great news about iPhones is that once they are eligible for the unlock, it happens automatically. All you have to do is insert the non-T-Mobile SIM card and restart the device. If you want to use an eSIM, just follow the normal setup process to do that. 

Hope this helps. 

I have never encountered a company that is so hard to deal with.. It’s like dealing with a Martian…  LOL  I tried the weekly contest, entered my credit card and in two weeks I got charged by 5 different company's (?) for over $500.00 (from $4.95 - $89.95) … Luckily my Credit Card Company froze my account.  I now have a new credit card and am inconvenienced by having to call businesses to change my re-occurring monthly bills - -  Not what I was expecting !!  -  I feel like T-Mobile exaggerated on their promotional WEEKLY FREE GIFTS and can’t find anyone to complain to, because the Representatives have no Idea what I’m talking about

Are you sure it was Tmobile and not a scam? I've never seen a weekly contest for Tmobile but have seen some in my spam folder.

for what its worth you might have to dig a bit deeper to see who exactly is the one doing the contest..as is you are talking about some contest you did where TMO asked for your credit card number (TMO does not ask for this. you would be paid with a pre paid card) in a thread asking about unlocking a phone..one has zero to do with the other.