No State Pension years recorded while working full time

Hello, I am a French citizen and moved to the UK in July 2018 and have been fully employed since by the same company. When checking my State Pension on the HMRC portal, I was shocked to see that my record displays gaps whereas National Insurance was paid via my employment (The HMRC pages says "You do not have any years on your record..."). I sent a letter with all my P60 and payslips from July 2018 early July this year but haven't received a reply yet. What is the expected answer time for this kind of request? This is obviously very worrying to see that no contribution was taken into account after all these years and would really appreciate some visibility on this stressfull matter. Thank you for your help.

I read online that HMRC may take more than 12 months to reply to these cases, is it really the case? I am very concerned that my retirement contributions for the past 6 years were not taken into account and seeking reinsurance. Does anyone know how much time it would take to get a reply from HMRC on this topic? Thank you

Hi,
We are  currently working on letters that were received in January 2024. 
Thank you.

Hi Pierre,
Based on the information you have provided, we are presuming that you have already written to HMRC with details of the missing National Insurance contributions from your employment.
If not, you will need to do this, providing names and addresses of your employers, tax years concerned, payroll numbers (if known), copies of P60, P45 or payslips, and your personal details. The address to write to is:
Individual Caseworker
PT Operations North East England
HM Revenue & Customs
BX9 1AN
If you have already provided this information, the team who will deal with your letter, are currently working on post received on 24 March 2024.
Thank you.