Interest charged on zero balance

I have just received Self Assessment Statement which details balances from January 2023 to January 2024 with two payments I have made clearing down my amounts owing to HMRC - both payments (for 21/22 and 22/23) made before Jan 31st both years. The statement shows a 'Balancing Payment due for year 22/23' of zero but then on 10 March I have been charged £529.99 interest with the comment 'Interest is running on the amount to pay. Please pay it now' The statement is showing nil to pay, apart from this new interest charge. Anyone have any ideas? Thanks.

Hi 

We would need to access your record to check why interest charged. You can contact HMRC at Self Assessment: general enquiries

Thank you