Cancelled Policy but Ooba still want payment

I cancelled my policy with them in July already and I sent them the info on my new policy as they requested. Still I keep getting reminders that my premiums is not received and every month I have to again forward all the emails about the cancellation. I would appreciate it very much if they can get their ducks in a row and stop this. Just now end up with a bad payment record because they cant get it right. Thank you.