Long wait for CF83 request response

Hello, On my Government account I see that I'm eligible to make up 12 missing years of NI contributions. From 2006-2018. I reached state pension age in 2018 and have only 8 qualifying years prior to leaving the UK in 1979. So until I pay to add years I do not yet qualify for any state pension. I plan on paying all 12 missing years. I've retired and moved to the UK in 2023 and plan to continue living here. On my account I'm quoted at Class 3 rate for the 12 missing years I wasn't sure if I could make up those years at Class 2 rate (as I was self employed in USA for all of those 12 years) as I was no longer living abroad and had passed state pension age. I sent a CF83 and cover letter in November last year seeking some clarification on this but have had no response. On my HMRC account it shows receipt of a form in November last year but not which form or any progress. Wondering if there is any way I can check on the status of that enquiry. Not sure who to call or how to follow up on this.

Hi Brian,
Looking at the timescales for the area I think will deal with you application, this should have been done by now.
Can I suggest you contact the NI helpline on 0300 200 3500. Lines are open 8am – 6pm Monday to Friday.  
They will be able to check we have your application and when it should be dealt with.
Thank you.