contract cancellation

so irritated by what happened, i called on the 7th of September to cancel the phone contract, they sent me an outstanding amount with the reference via sms. i paid, and called to confirm if they received the payment, and they said yes. a month passed, today when i check my statement then to realized that they continued to debit again this month on the 20th, like really now?? when i call, the consultant cant even explain what's going on, and she ended up keeping quite without any reply when i ask questions, thats rude. *** fix your mess please, i want the account closed and my money back....!!!