Cell C internet service

After my fibre was installed at my home I've selected Cell C as my ISP and was connected to the Internet within days, which was in December 2018. On the 2nd April 2019 my internet service was switched off for no reason where after I've sent a few e-mails to Cell C via their website and received a ticket number every time (5 ticket numbers). Cell C contacted me twice and spend 45 minutes each time going through the steps to connect, it connected but still showing no internet service. On the 12th I've learned over the news that Cell C's staff is striking and then only I realised what is happening. I phoned them trying to connect with the same result. On the 17th April I've sent them an e-mail again stating that this month to month contract is cancelled. After that cell C contacted me 4 times and every time I told the they've breached contract by switching off my internet service and late yesterday afternoon(6 May)I received an e-mail stating there is a Claw Back Fee of R3221.06 which I have to pay and the termination date of service will only be 31 May 2019. Cell C breached the contract and I have to pay - What is the legal way to resolve this issue?