Double billed

Mtn wrongfully debited my old bank account that I canceled them from debiting months ago. I've been doing eft payments for many months now and I did eft them on the 25th however a debit order went off my account on the 26th. I then logged a call to request for a refund and to my shock I was told it takes up to 21days. Mtn you wrongfully debited money that was meant for my late grandmother's ceremony which is taking place this coming Saturday. Please return that money back, it's not mine and you are disgusting for even taking this long to return what's not yours. Capitec: Debit Order -R209.75 from SAVINGS ACCOUNT; Ref MTN SP BA***