cell c submitted x2 contracts but i only signed up for x1

i took a cell phone contract via telephone last year may 2023 . when i recieved my device via the couriers after 7days i saw that they sent me x2 devices with x2 contracts . i then called cell c customer care the very next day and reported that they sent me x2 contracts and x2 devices when i only agreed to x1 . they customer care agent then apologised and said that the agent made a mistake and did to contracts on my name . they then asked me to send back the x1 device and they will cancel it and just charge me for x1 contract as per my agreement . i did as they asked and still was been double debited at the end of month for x2 contracts . i kept calling them and the agents kept telling me they will sort out the mess up . however that 1st month they had already blocked the phone to prevent me from using the data,minutes and sms .when i called to ask why have they done that , the agent then told me i have not paid my monthly fee of R249.00 , i then told them that they double debit me and i was asked by cell c account to reverse the debit order because of the mix up with them sending me x2 contracts by mistake .they told me it will take between 12 to 24hours to correct the account . but still had no joy .i then spoke to a manager thinking i would get the help i need .i sent them proof of my account showing double debit,proof of courier bill to show extra device was sent back ,aswell as an afidavidt .today is the 14th march 2024 and nothing sorted.i called the customer care department one last time to see if can help me since been 1 year and nothing .the manager of customer care named tsepo abused me saying i have not paid since may 2023 and i am liable for that , so i tried explaining the problem i been having with cell c and that that nothing has been sorted since a year and i have not used the minutes and data which was due to me and that it not my fault for they mistake aswell as i been calling them every week for asistance with no joy.i do not know what else to do as this people working there do not know themselves the process and its affecting my personal life now because im listed on itc (credit bureau) and i do not think its fair to me .please help me.thanks