Ethekwini Municipality not refunding advance payments

I sold my property in Durban and transfer took place on 23 April 2021.

I have been asking for my deposit and excess rates paid since then. I received an account in may where they charged rates, in advance, for May, June, July and August 2021.

I logged calls on their website, uploading all required documentation. I phoned them, I tried to enquire via the reference number provided - no response.

Why is this such an issue? ***** again?