Trade in/Upgrade with great caution, ATT deceiving tactics

I have been on the phone with ATT trying to clear up my so called "upgrade" no less than 8 hours since about July. Upgrade all began at Costco, prior to my trip to Mexico for a short vaca. During my trip, my new iPhone 13 dies, apparently there was a hardware issue that APPLE support could not fix, nor could the Costco kiosk people. In the mean time I wait for the box to send in my upgrade....tic Tok tic Tok....I call att trade in department and they say, well give it another 5 days or so you will receive it. I ask can't you just email me a label so I could send you my phone...nope. Costco eventually takes the phone as a faulty unit as they called it and I repurchase a whole new iPhone 13, with the option to trade in of course. This new phone works as it should no issues, now at about 15 days after the purchase, still no box to return the phone. I call again, sir dont voury "with a strong accent" I have notes indicating you have not received the box. So I eventually speak to someone who gladly emails a label, great I send in my phone immediately, considering all the madness still within their 30 day window. Months pass still no credit issued. After speaking with a rep, I am told that they were aware of all the issues and a credit would be issues on next billing cycle. The billing cycle comes and goes, still no credit!!!!! I AGAIN call ATT trade in department, now i'm told I missed the 30 day window and because of this I would not receive my credits. I laugh out loud and say, nope, I have ups receipt in my hand, as well as your history would indicate otherwise. After some back and forth of silence keeping me on hold, sir, yes we did receive the phone. BUT we see the IMEI does not match the phone you were supposed to turn in, I say (Edited per community guidelines). They now tell me I sent the wrong phone, they have now had the phone about 4 months and fail to inform a customer of this. As it turns out it appears they received the phone sure, the phone they received was the phone recorded on record to be returned but apparently because it was not the ONE to be traded in they cannot accept it as a trade in. People be cautious with this deceitful tactic from ATT. At the moment I have lost an in perfect condition iPhone XR that I could've given to one of my kids, and I am paying full price for my iPhone 13, I am livid. A series of promises for call backs, NEVER HAPPENED!!!! Sir we will call you back before 8pm with an update, crickets........

So I ask that you be very cautious when doing this trade in there is no guarantee to the credits, this company isn't what they used to be. And by the way I am a pacific bell customer, dating back to about 1997!!! Loyalty means crap from them!!!!

Revenge...I dont know, but I am headed back to the Costco kiosk and switching to Tmobile, guess what? They will pay my phone off and....save money on my bill. 

ATT I hate to leave but after over 8 hours of trying to fix this and your companys level of incompetence to fix a minor problem leaves one much to desire. In todays day and age retention of clientele should mean everything but perhaps the large conglomerates don't give a crap.