Payment made for 2022/2023 tax year not shown on new 2022/2023 simple assessment

I received a simple assessment on 24th August 2023. It advised that I owed £4,396.16 for the 2022 to 2023 tax year. This was paid in full on 11th November 2023 and I received an e mail confirming this. This morning (9th August 2024) I received another simple assessment for the same tax year. This second simple assessment did not reflect the £4396.16 that I paid on 11th November 2023 and HMRC are now asking for it again, along with an extra amount. The payment does not show on my HMRC account despite the fact that I know that I saw it referenced on my account back in November 2023. How can I get this corrected?

Following as my MIL has had similar only her payment was made on the 27th November. She has received a letter saying her tax due hasn't been paid and strangely the 'unpaid' tax is not accruing interest.

I have since managed to contact HMRC and received a satisfactory response.

How did you manage to contact them? She is 92 so will have to give permission on the phone for me to talk to them. Having spent about 3 hours on the phone a few weeks ago about another issue I am not happy trying again only to be cut off after 1hr 10mins.

It took 10 mins to get through at 8:00 on a Friday - maybe I was lucky! I was advised that HMRC always report the total amount owed for a tax year within each and every subsequent simple assessment. If they find an extra underpayment they will advise the total amount again, even if a payment has already been made to clear the amount from a prior simple assessment. They could see the first payment made by me even if I couldn't so I now only need to pay the new balance. I would advise contacting them at 8:00am on a week day morning; I only waited for 10 mins or so before being able to speak to someone. Did you receive an e mail confirmation of the payment on 27th November or did you take a screenshot of the payment confirmation screen? Do you have a bank transaction statement that confirms the payment to HMRC?

Hi,
As we are unable to check personal records via the forum, you would need to contact HMRC to discuss this.
An advisor should be able to check the payment and correct the record where appropriate.
Contact us between the hours of 09:00 and 18:00 as the advisor would need to transfer the call to an internal department.
Income Tax: general enquiries
Thank you.

Update, it was sorted by phoning the number on the letter sent which isn't the same number as general equiries. They were very helpful (much better than the general helpline). Unfortunately MIL had deleted any emails she might have been sent any never took any screen shots as she thought it had been paid.