Data contract

I app**** online for data contract with home cloud and they took 3 months to deliver the data sim card while they were busy trying to debit my account, after 3 months they delivered the sim and activated it, I told them I don't want their Services anymore because they are not reliable and told them to cancel the contract but they wouldn't cancel the contract, I payed for their prorata amount which was R333.33 but still wouldn't cancel my account, I asked for the managers contact details from Andile which that was my account manager and she gave me Ismail e mail address and I sent him an e mail so that he can send me the cancellation letter with the company letterhead but couldn't bother to respond on my e mail until today, I really don't know what to anymore please assist guys as my name on listing