Municipality drags it's feet on rates refunds

I sold a vacant erf in the first half of 2022 and was obliged to pay 3 months municipal rates in advance. This resulted in a refund becoming due after transfer. It is now 8 months since the transfer was registered and the refund has STILL NOT BEEN REPAID. Conversely, my monthly account was a few days overdue at one point, this happened once over a period of over 5 years. The credit department was all over me IMMEDIATELY. They added a charge to the account for sending an email demand and threatened large interest penalties. Is it worth lodging a similar demand for interest on the unreasonably overdue refund?