Cell C - worst service ever!!!

I signed a new Fibre contract with Cell C on 30 August 2018. Included in the contract was 3 months free subscription, installation and the Black binge package for 3 months. The free subscription, according to the contract, would start once the Fibre was activated. They did the installation around September, however there were problems with the connection and it was only activated on 15 January 2019. I communicated with Cell C via email and telephone continuously during this time period, keeping them up to date regarding the fibre that was still not working. At the end of January they billed me a pro-rata amount of R128.00. I advised them that this was wrong as my free period only started on 15 January 2019 when it was activated and I reversed the debit order via my bank. At the end of February they billed me for full contract price. I again advised them that this was wrong and that I should only be billed a pro-rata amount at the end of April and the first full amount at the end of May. After that I received 2 calls from Cell C to advise me that my account was in arrears even though I still continued to contact them and advise them that they are in breach of contract by billing me while I am in my free subscription period. Last night, 23 April 2019, they switched off my fibre and when we called them they said that my account was suspended because it was in arrears. Apparently they couldn't assist me over the phone as the staff are on strike, however this is no surprise as I've been logging calls regarding the Fibre since September 2018. Their service is despicable and regardless of how many times I've told them the same story, they just keep on asking me to pay the money that is not due to them.