Insurance Cancellation

On 20 May 2024 I canceled my Santam insurance that covered my Samsung A33 that I took by contract at MTN.I was billed a cancellation fee in June which I understand as per Ts & Cs however I have been billed for July and August as if I never canceled the insurance.I have contacted Santam about this matter and they advised me that it's canceled on their side and I should enquire with MTN as they handle the billing.When I contact MTN they advise that it's insurance matter and have no clue on why I'm still being billed.I have provided invoices for proof and have asked for refund but I have been going back and forth as no one has answers for me