Cell C delivers handset to wrong address and blacklists me for not paying the account

I took a contract with Cell C (telesales) when I was a varsity student - December 2015. They promised to deliver my handset in 3 days and we had an agreement of a debit order for every 5th day of the month. They only delivered sim cards that same month and promised to deliver the handset later. In January 2016 I received a call from them asking for my current address to deliver as I was residing at campus residence- still my handset was not delivered. I did not receive any calls or sms from them until April 2016 when they called to say I owe them. I told them I do not own the phone and I was advised to log a ***** case and so I did. From then they strarted debiting amounts like R12, R10,75 every month sometimes twice or three times a day. I followed up with the case and I got no response. It turned out I had now 2accounts with them. I had to close my bank account to avoid the bank charges from the debit orders that bounced when I did not have money in my account. Later in 2016 I received calls from debt collectors threating to blacklist me. I told them my situation and they escalated the matter with Cell C. Their response was that I am liable for the account as there is a proof of delivery to my address. The proof of delivery had the wrong address , a signature that was not mine and my mothers cellphone number. My disagreement on that proof of delivery was diregarded and I kept getting threats from debt collectors. Eventually I got a hold of the ***** department at Cell C and I sent them relevant documents to prove that I am not liable for the debt. They made a few follow ups and went quiet. January 2017 I got a job and i could not get financing for a car because of my bad credit record with cell c. I contacted their ***** department again and they said they will investigate. I ended up paying a debt of R2400 to debt collectors so that I could clear my name. Last month the ***** department got back to me and confirmed my innocence and said they will call to make arrangements to pay me back the amount I paid to debt collectors. I opened bank account and the bank told me that I still have an amount listed on the ITC with Cell C for an amount of R270 besides the R2400 that I knew about. I went to cell c to check and they said they will get back to me- I am still waiting for response. I got a free credit report from TransUnion and it indicated that I have at least 3 accounts with cell c that have been written off due to no payment . I cant apply for any financing whatsover because of Cell C.