iWYZE not so wise

So these insurance company has decided to blacklist me. I took out insurance cover with them upon purchasing a vehicle. When the month ended I called and told them that I have found another insurer with cheaper premiums. They acknowledged my cancellation and promised to send me cancellation letter. They never sent the letter and after calling them a number of times I was told that they don't have my records on their system. They kept deducting until I changed my bank account. When I checked my credit report, I realized that they keep updating payments as if the insurance is active and in arrears. Never go for this insurer as they are nonsense