There are models that are indeed carrier locked and it's not up to Samsung to unlock. That's between you and that carrier or however the model was unlocked the last time.
You left out the full model number in question so I can't check if that's the issue. It has been in the past and stories like yours happen next.
I sent my phone for repair and it has been locked back to one provider.
I spent at least 5 hours on a phone, calling from a different country to unlock my phone.
During these time I had to buy another device because I was unable to use my Samsung with another provider.
I am a loyal customer of Samsung and using their phones for more than 15 years, but the Customer Service in the US is absolutely nightmare and should be going through the proper training process.
Everything from the very beginning went wrong, my details were not taken correctly and a repaired phone has been sent to the wrong address. I never received any information from Samsung about problems with my postal address and only after I contacted them directly and talked to the couple of Samsung representatives, spending a lot of time on a phone, I was able to detect the problem and sort it.
Now I'm struggling with the locked device. I called my network provider, but this phone is shown as unlocked in their system and they can not help. I believe that Samsung representatives are absolutely useless, as they were washing my brain 5 times for about 1 hour each time and nothing changed.
Now I have no idea who to speak with to solve the problem.
I also would like to understand who will repay all my unreasonable expenses for phone calls and additional device I had to buy?

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