Unable to cancel a contracted that has lapsed.

I took a 24 month contract with MRP Mobile and they continue debiting my account after their 24 months has lapsed. I have stopped using their sim card and they keep loading data on it. I have called no answer, sent emails no respond. But now that I have stopped paying they are sending me sms threatening to hand me over. How do I cancel this contract???

How do they continue a contract that has passed its agreement terms??