Telkom won't stop deducting money from my account

I am very disappointed and disgusted with the customer service at Telkom. I ordered a router over the phone with them and they gave me a wrong one. I informed them, they sent a courier and promised to cancel the contract after receiving they received back the wrong router. They never cancelled, and they kept on deducting money meant for my other debits from my bank account. I called them and they said I must send proof of my courier slip. As pathetic as that sounds, I did that but still they never cancelled my debit order. Yesterday on the 1st of September they continued to deduct even though they acknowledged 3 weeks ago they received my courier slip. Today after waiting for 30 minutes on the phone I was told they cannot cancel the debit orders on their side but sent me their link where I was "supposedly" going to cancel the debit order myself. I opened the link, registered my details but I received a note that I do not have any account to manage. That makes sense because I did not even use their router. I had to return it back when I realised they sent a wrong. Telkom is making me sick. Inconvenience is an understatement. I am so disgusted with their service