Answer my email and stop debiting from my bank account

Last year august I got into a contract with DebtReview, recently I've sorted my financial struggle out, so I've sent them an email to cancel the contract, because right now I can afford to pay for my debt, they did not respond to my email, I tried to call them but they will always say hold on, no one has ever given me an ear to hear me out what I need from them, so they keep on debiting from my bank account and their debit order is irreversible