RAIN STILL DEBITING DESPITE CANCELLED SERVICE

I cancelled my rain sim card during April, I woad then advised that the cancellation would take effect on the 1 May and was debited for usage on this date. The service was cancelled and the SIM card does not even appear on my profile. I have just debited AGAIN today with no option to cancel or remove my card. I really need to get this resolved and get my money refunded.