Carrier unlocked Iphone XR locked after reset and update to iOS 16.2

gramps28 wrote:

Once a phone is carrier unlocked it can't be locked again. It can be blacklisted if it was reported list or stolen.

The only thing I can think of is the phone was jailbroke and after the reset it went back to factory settings. I suggest contacting the seller if they still have an active account on ebay.

An Apple support engineer connected to my phone remotely and said that there was no hacking or other illegal actions and said he would contact the seller and directly to T-Mobile. But a small problem is that due to my level of English, I may not explain the problem correctly.
And I had a question about T-Mobile email, do they have it or can I just call there?

syaoran wrote:

Sprint was dissolved into T-Mobile what seems like ages ago now.  Sprint as a carrier does not exist anymore.  As mentioned, devices do not relock after being factory reset which illustrates that some sort of work around or hack was used.  If you can't get a response from the person you purchased it from and convince them to take it back for a refund.  There is nothing T-Mobile can do.  You do not meet any of the T-Mobile SIM Unlock Requirements and you mention the device was stolen but not blacklisted.

https://www.t-mobile.com/responsibility/consumer-info/policies/sim-unlock-policy

I didn't say the device was stolen. I said that Apple support confirmed the cleanliness of my phone.

As I understand from the answers, you just need to deal with the seller.
He still sells phones on ebay. Is it possible, after 3 years, under US law, to demand a return from him, since he provided false information about the product?