Bad service

I cancelled my insurance with Dotsure after a high premium for my car. Called and the cancellation was done with no issues that was the 25th of March. On the 27th of March a debit for the premium went through to my surprise. I then took it to myself to call again requesting them to refund as I already had cancelled my cover, to be told to send a bank statement for the refund to be done. Took the initiative to get the bank statement and send it through as requested. No one got back to me. I then called them again to find out what is happening and that was on the 2nd of April, spoke to Jason who advised that they are still investigating and will call me back in 2 minutes time that was 72 hours ago. Wow. Dotsure if this is how you conduct your service I’m glad I cancelled this cover. How long would I have been told to wait for a claim? 24hours? Do the intricate math!!!