Charged for a phone i did not take on my Contract

I am so mad about Telkom Kenilworth Centre. They charge me for the phone that i did not take - Huawei P20 Light with a number ********** 694 since July 2018. The store acknowledged that they made a mistake by billing someone's phone on my account. Until today they have not credited my account. I have reversed debit orders twice , thus September and October. I did an eft of what i owe them.They are charging me payment rejection fee. Now they have suspended my services, why must i suffer like this? The billing department is saying they cannot reconnect my services they require an instruction from the store, when i left there they told me someone will call me in 15 mins. I went back after 4 hours they said i may receive a call in 2 to 3 days. How unprofessional is that? Telkom has drained me financially and emotionally. All i want is for them to restore me to the position i could have been had this not not happened