New Immigrant moving to the UK - Filing tax return for 21/22

I'm a new immigrant moving to the UK on 28 March 2022. It means my stay in the UK was 11 days within the whole tax year 21/22. Recently, I received a letter from HMRC (June 2023), requesting me that to file a tax return ONLINE for 21/22. The letter also said HMRC will not send me a paper tax return. On my account page in HMRC gateway, I can see the link for me to do self-assessment for 22/23, but not the for 21/22. I cannot locate the correct button for me to file / amend the self-assessment for 21/22. What am I supposed to do ? Also, I want to know what is the proper channel to contact HMRC on this matter ? I've written by post to HMRC however the reply (if they do) will take a month time.

Hi,

If you contact our Self Assessment team by clicking 'ask online' and request to speak with an adviser, we will be able to review this and advise you how to access the 2021 to 2022 return if it is required.

Self Assessment: general enquiries

Thank you.