UTR No has yet to receive

Both my husband and I had registered for self assessment on 2 October 2023 in which we have clearly mentioned we were applying the UTR and split year treatment. However, we haven't received any letters or feedback from HMRC to inform us the Unique Taxpayer Reference (UTR) which is over 3 weeks. Also we have kept checking our online personal tax account on HMRC website or HMRC App, there are none of UTR record shown there. This is our first year for the self assessment, and we shall submit paper forms by 31 October 2023. Without getting the UTR, we both can't do anything. We have raised the queries via HMRC online chat but nothing can help there. And we also called HMRC several times and finally we got a helpful staff to reply us they will pass our cases to the responsible team for investigation and what we can do now is just waiting. As the submission deadline is approaching, we are so frustrated and afraid we will be late for submission. How can we get the UTR as soon as possible? And we got to submit the SA109 form, can it be done online if we haven't got our UTR before the submission deadline? We really need some help.

Hi N.L. So,
If you contacted HMRC then a referral would have been sent to review your registration submission.
From the referral the UTR is normally allocated in approximately 2 weeks.
The SA109 cannot be filed online using HMRC software.
You would need to use 3rd party commercial software or submit a paper tax return:
Self Assessment commercial software suppliers
When the notice to file your 2022/23 Self Assessment is issued you will be given 3 months and a week to file the tax return before late filing penalties are charged. 
Thank you.