POOR SERVICE

I had two policies with FRANK.NET for 4 years. I cancelled my policies in July 2018. They still deducted money and I had to reverse debit orders every time. I see that FRANK .NET still reflects on my Credit report and I phoned them to give me a letter that I can send to the credit bureau stating that I am no longer paying them and that I have cancelled my policies. Today I get letters stating that they had to cancel my policies due to non payment. All I want is a letter saying that I don't have any policies with them anymore so that my credit report can be fixed. Is that so difficult? Customer service is poor!