I can't close my self-assesment my request gets rejected automatically

I moved out of the UK, I wrote a registered letter to HMRC 2 months ago requesting the closure of my self-assessment and they never replied even though I was notified that the letter reached the destination. No one closed my self assessment and no one answered my letter in any way. I then tried to close the self-assessment through the Stop Being self-employed link on the Government page and my application keeps being rejected automatically stating that the address provided does not match the records. I checked and there was nothing wrong with the address. I though updated the address and my application keeps getting rejected over and over. I called HMRC and I was kept on the overseas line for over one hour and no one replied. Please from the bottom of my heart, help me close my self-assessment as no one responds on phone or straight mail or email. I am up to date with all my tax returns and payments to HMRC. It is not fair that people are treated so badly. I moved out of the country and I want to make sure all my stuff is closed. Please help me solve this issue! Even if I fly to the UK personally, I don't think there is any way that I can talk to a human being employee at HMRC who can help me. Thank you very much!

Hi Beatrice Baiu,
We are sorry you are having issues trying to close your Self Assessment aacount.
If your letter was sent 2 months ago then this should have been reviewed by now.
As you are not able to submit the request online we would need to access your record to check on the progress of your letter.
Self Assessment: general enquiries
Thank you.

In the meantime, I was able to talk to someone on the HMRC chat and they told me that my Self-assessment was closed and that a letter was sent to my new address, but I have not received anything so far! I don't know what to do! Thank you!

Hi,
If you have contacted HMRC and the record has been closed then once the letter is issued it can take 10-14 days to arrive.
If you wait for the letter to arrive this will confirm record closed. 
Thankyou.