Cheque cleared Mar '23 but no confirmation

I sent HMRC a cheque for more than 8K last March (2023), being gaps in my NI contributions (for the state pension). The cheque was cleared the same month but my online record has not been updated, neither have I received any replies to my letters regarding this . Today I phoned the helpline & was was on hold for just under an hour, so I gave up. I am so frustrated. Can anyone help / advise at all? Many thanks

Hi,

Sorry that your payment that you sent to us last year is not yet recorded on your National Insurance account.  

The best way to deal with this would be to contact our National Insurance team.  

National Insurance: general enquiries

Our Helpline opens at 8am Monday to Friday and if you could call as soon after as you can then it should be easier to get through.  

If you would rather write to us then our postal address is:-  

HM Revenue & Customs,
PT Operations North East England,
BX9 1AN,
United Kingdom

Thank you.