Standard bank and bettersure have been ****ming me since 2021

I have life cover insurance on the standard bank mortgage bond . I sold the house in 2021 but the insurer continued to debit my account to date. I called bettersure to cancel the insurance they told me they need a cession release letter from standard bank in order for them to cancel. I called and sent an email to standard bank requesting that letter on the 5th of January 2024 . I have not received it yet , the insurer will be debiting my account again this month for insurance on non-existing item. When I call standard bank to follow up , my call was transferered 5 times and then hanged up. I never made an application directly to bettersure, I did it via standard bank, I ask my self why the interlink /communication between standard bank and bettersure doesnt exist upon cancelation. Standard should have communicated with bettersure that the bond does not longer exist and cancelled the insurance. This is just a ****. I want to cancel and I want a refund of all the premiums paid after the bond was paid.