Paymentt issues

Everything was going ok until Prime Meridian tried to debit my account on the 23rd September instead of the 25th September and the debit order bounced costing me a bank charge of R107.00. They send me an sms to pay my account with a link I tried to use the link to pay and the link didnt work. So I used the bank details to pay via EFT and I sent a proof of payment. a few weeks later my account was debit by Prime Meridian. I sent and email and they asked for the proof of payment. And nowI am not getting any respond for the refund. No calls , no emails . What do I dom cancel the insurance/