Try cancel my subscription

My company closed so I had no work I called Rain and advise them about my situation and on the called told them to cancel as a call center all calls are recorded so there is verbal proof that I have called and canceled the problem is that rain is desperate for clients and money that they still billed me without my knowledge I haven't even use the internet because I canceled they billed me R11500 that I owe it's there mistake that now I have a debt that I don't deserve and many people complain about the same issues please rectify your mistake.