Rain exploiting users/customers

I cancelled my service with rain 2 months ago They told me the March debit was the last one To my surprise the debited me again in April and told me they will refund after their courier company fetch the router The router has been off for 2 months now, they are not sending any courier and they keep on debiting my account,I would not recommend it to anyone, I want my money back into my account. I have been calling to number of agents and they do nothing