Lost payment and HMRC say assessment late

Paid HMRC owed tax and money mislaid but traced and added to account. Now require interest. I wish to resolve this as you had the money. HMRC claim I was late to return self assessment forms and want to fine me. I have receipt for me sending as signed for 1st class. I wish to resolve both these issues in one phone call or a face to face in my local office. Please provide a phone number

Hi

The Self Assessment helpline is currently closed and will reopen on 04/09/2023.
For queries before then you need to write to us or contact us by webchat here Self Assessment: general enquiries

Thank you