Debiting my account even though 24 months has passed and I didn’t renew my contract why are you still debiting my account.

My contract with CellC ended in April. I called in March to indicate that I would not renew it. The consultant said the last debit order date would be in April. On the first of May my account was debited, I called your customer service line and the consultant said someone would call me for a refund after 2-3 days. I called again after 5 days and I was told the same thing...no one has called for my refund.