Debit my account after stopping my cover

I stopped my insurance with Santam and they still continued to debit my account.

I've been with Santam for 15 years. This year they hiked my premium from R5600 to R7200. Following this I was able to get better cover at less than half the price at another insurer. After cancelling my cover, they still continued to debit my account- as if this crazy premium increase wasn't enough, now they are just taking my money for nothing.

I used to have the utmost respect for Santam, but clearly their great service has changed to greedy money chasing. I want my money back!