In accurate billing on accounts

Telkom billing/accounts department is very bad... On the 28th of May 2021 I canceled the insurance contract with admin plus and I was advised that the last debit for that insurance was on June... And not we in July am still being billed for a policy I canceled. Even I I canceled a phone contract I was requested to pay. Their billing system inconveniences people and is very bad and I need to be refunded