Metro by T-Mobile review: Customer service

I have been a customer for 20 years. I currently have 3 lines, for which I pay $80 a month. My mother, who has one of the lines, went into a Metro store to have switch her old phone to a new phone, nothing more. She actually paid $56 dollars for this in the store, for which there is a receipt. Later that day I noticed an additional charge to my account, for which I contacted customer service. Instead of eliminating the charge I was told that my last bill was only partially paid (which was untrue) and when she was told this wasn't true she then said that services and insurance was added to the line, which also was not true. The call devolved into a negative situation, I became frustrated when she refused to listen. I have had some negative experiences with Metro customer service in the past but this was absolutely the worst. So much so that I had to make a complaint. Now I still have this charge on my account when this was actually paid for in person. I would like a resolution to this issue as soon as possible.