Struggling to get removed from Self Assessment

I stopped my self employment on 20/01/2023 and I have been working for an employer since 23/01/2023. I used an online form to notify HMRC of this and I also included this information on my final tax return submitted on 09/04/2023 but I continued to receive regular emails asking me to complete a self assessment tax return for 2023/24. When I contacted HMRC several weeks ago via live chat the agent found the online form that I had submitted and informed me that I would be removed from Self Assessment, however I am still receiving emails asking me to complete a tax return for 2023/24 and, having logged into my tax account, it appears that I am still registered for Self Assessment. I have again today tried to resolve this via live chat but I get a message that agents are unavailable. Could someone please advise what might be the best course of action for me to be removed from Self Assessment.

Hi,
I am sorry that your record has not yet been updated.
To check this has now been actioned we will need to access your record.
You can contact HMRC at Self Assessment: general enquiries
Thank you.

I have returned to the webpage as suggested and have attempted numerous times to contact an adviser via the live chat facility but repeatedly get the message 'Our advisers are not available to discuss your query at the moment' Is is possible to write to HMRC to try and resolve this issue?

Hi,

You can write to us at:

Self Assessment,
HM Revenue and Customs
BX9 1AS
United Kingdom

Thank you.