Metro by T-Mobile review: employee stealing

My mother went to pay her bill at this metro pcs today August 2, 2019, at 12:46pm. The invoice of the only receipt she received is: *107244* My mother was told that her new phone was $150, she gave the employee (EMP ID: KIKITO), $160. She received no change back, and also no receipt for this. The next transaction, the employee told her the phone case she wanted was $35, so she gave him $40 dollars, and he return exactly $5. For the phone case only, she got a receipt saying the phone case was $12.00 with taxes $13.07. The employee put down that my mother only handed him $20 dollars. With both transactions, the employee pocketed about $30. I called customer service and was told all they could do was file a complaint and that there most likely would not be a follow up. I was told that the best thing i could do was speak to the manager of that location. When I spoke to the manager, He told me his name was Michael. When i started explaining the situation he told me that he does remember my mom, because he was the one that took care of her when she was there before. Whenever i asked him what happened he would say that she did not hand him all that money. Lastly, when i mention reporting it, his tone changed and he said He'd give my mom $30 to keep her happy.