T-Mobile USA review: Billing and service rep.

On 6-27-2-23 I went to T-mobile to upgrade my phone. The sales person that helped me seemed happy to help me and we started to process. I told him that I was on the senior plan and wanted to keep my bill as low as possible as I was about to retire. I was clear that I would have a payment plan for the new phone but did plan to pay off the phone balance in a couple of months. He said "not a problem and oh by the way it is the end of the month so I am giving you 2 phone lines for free." I told him I did not need more lines as it was just myself and my husband. when I got home there were 2 extra sim cards in my bag. I spoke to him again and he said not to worry they are free just give them to anyone. I did not given them away, I just put them in my closet with the boxes. When I received my bill I found that is was over 400 dollars for the 1st bill and over 200 for the second. I called customer service and they said they could not help me as as they could not verify my account. I wanted to cancel my service, pay for my phones and move my service to another company. Customer service said they could not cancel as they could not verify my account. I visited the store I originally went to and also another store and no one could help me. My account was sent to collections even tho I had cancelled in Aug. of 2023. I just want to pay for the phones and I agree I owe for those but not the back service charges as I had cancelled the account. Looking at some of the complaints I have read it looks like this has happen to several others and I have printed out those complaints for my own files. Eventually it was sent to collections for service charges. I have disputed those charges. Just let me pay for my phones and move on. If you can verify my account to send to collections you can verify my account to cancel my service and pay for what I owe.