they keep debiting me for a phone they have.

My mother Sarah Nobela took out an upgrade last year September with Autopage at Greenstone, the phone gave us a problem with in the week, my mother took it back the phone within 2 days of the upgrade, from my knowledge, as consumers if you return a phone within 7 days, you get a new phone. She then waited 2 weeks for a call from them, she ended up goint to the store to check with them then they gave her the same phone which she didn't accept and she left it with them but they keep debiting her, she doesn't have the S4 or the tablet. They don't wanna stop debiting her and they don't want to give her proper new working phones, they are very rude, from the consultants at the store to the debtors. They don't wanna sort anything out with her.