Vodacom is the worst company ever!

Im so fedup with vodacom. Its been 6 years that I have been struggling for them to clear my name. 6 years ago vodacom deliverd a parcel at my house. It was a vodacom router. I Accepted it and agreed to the payment every month for I had a Iphone on contract with them. The next day they deliverd another parcel. Another router. I phoned vodacom and made them aware of the problem. No one came back to me. They came and picked up the router after 4 months and said i will be refunded for the exstra router. Then I recieved a bill of R5000 and they stopped my contract and debit order on my Iphone and the router I accepted. I paid the R5000 to get my phone working again and then they again said they will fix the mistake. Now I have to pay the R9000 for something I do not have. I cant upgrade. And they are giving me a bad credit score so no other cellphone company wont help me. What do I do now?