Voluntary Contributions Abroad - Class 2 or 3?

I lived in UK for my first 25 years and return frequently. I worked after leaving school in the UK then went to College for 4 years before moving to the US right after graduation in 1982 where I’ve worked for 36 years and retired. I qualified with my Social Security record and UK employment for 3 full years NIC, and just began receiving a small payment. I would like to fill in gaps, but don’t know if I can pay Class 2 contributions or 3. I have read the distinction, but it’s not that clear. I have also seen the form used to apply but it’s centered around those just moving abroad. Also on my initial pension form Pensions received on Aug 4 I asked for VC information. I phoned on Sept 12 and again in early January and asked, but as of Jan 6 I haven’t received anything. I do have a Gateway account, I see my full and partial contributions, but no Pension Summary or mention of the amount I’m actually receiving now. Thanks

Hi John Heaps,
You have taken the correct action by contacting the International Pension Centre to request information about paying voluntary National Insurance contributions for previous years.
They will issue a letter to you advising what gaps you have, what rate you are eligible to pay, how much it will be and how to pay.
You may wish to contact them again to ask for a timescale for when you are likely to receive their reply.
Their contact number is +44 (0) 191 218 7777. Lines are open from 8am to 6pm, Monday to Friday.
Thank you