Carrier Lock Restricted by TM, iPhone 13 Pro brand new paid in full from Target

Please help. I've had this brand new phone for 2 years now, bought accessories, etc. Set up phone without SIM, logged into my Apple ID and was finally ready to use it with  my carrier and is sim/carrier locked. I’ve reached out twice at the beginning of the year through Chat. Provided IMEI and was told via Chat this phone was not under TM carrier Network. Paid another website to hopefully unlock it, and couldn't because my sims was restricted to TM. Went to Apple Care to see if they could help me. Apple plugged in my IMEI and was told this phone is carrier locked by TM/Sprint Network. I reach back out to chat today stating that I bought the phone brand new from Target, its been 2 years now that I haven't been able to use this phone and from my understanding should be eligible for free unlocking. Instead of help I recvd attitude with the rep keeping track of the two times I reached out prior??? The bullying continued with the chat rep stating TM has the sole rights to deny my request to unlock… WORD FOR WORD and also stated he wouldn’t because my phone hasn't fully been paid off ( it wasn't purchased through TM / nor do I have an account, and have no relationship with this carrier, it was paid in full by Target… so I'm confused as to how this rep would have this information???)… therefore TM nor Sprint will unlock this phone and that Target lied to me. Forget the phone for a minute, what kind of CS is this !??! I stated I paid for this phone, no receipt was asked for, no follow up questions to make sure he understood since this doesn't make any sense ! I also plugged in my IMEI through TM “compatibility” and was accepted…. How, if my phone isn't paid in full? !! Now for the phone.. I asked if he could provide me this information about the phone not being paid in full .. WORD FOR WORD again.. “Nope bc we need to gain access  to the owners account to see that” and that was it. I am disturbed with the professionalism or lack thereof. This is sad. Can anyone help me get to the source, please?

I went to Target today to  get the receipt to show proof the phone has been paid in full. I went to Apple Care yesterday, they took my phone to look up the IMEI and informed me that this phone is carrier locked to T-Mobile/Sprint Network. After I found that out I went to T-Mobile Chat yesterday as well and requested my phone to be unlocked and the TM rep mocked how many times I went through Chat to figure out what's going on with this phone since every store and website service shoots me back to TM. The chat rep denied my phone to be unlocked because the phone isn't fully paid and I am confused as to how this is true if I have never been affiliated with TM whatsoever, no account, no number. The phone was bought with no sim so I could pick any carrier that best fits me. The rep confirmed the phone is locked to TM but denied to unlock my brand new phone because somehow on his end the phone hasn't been paid in full ?? BUT IT HAS..  He is giving me a hard time, not answering my questions and its a joke to that rep. He basically said in fine print “ TM has sole right to accept or deny my request. I am gathering all my information and going to corporate with it and hopefully someone will take my proof and facts into consideration and unlock this $1200 iPhone that I’ve never been able to use. 

I really appreciate the feedback and will follow suggestions and hope it works. Fingers crossed !