Double CF83 forms

In August 2023 I sent a CF83 form for Class 3. Later I learned that I am also eligible for class 2 since year 2019/2020 and a week later I sent another CF83 form for Class 2 and Class3. In May 2024 I received a letter from HMRC "Voluntary Class 2 eligibility letter". I filled a form and sent it back to HMRC. The record shows it was received by HMRC on 22 May 2024. Later I received another letter from HMRC to pay gaps, but only Class 3. I think it is a reply to my first CF83 form. It was 3 gap years before 2019/2020 for Class 3 payments - 2010/2011, 2013/2014 and 2016/2017. I made Class 3 payments for these three years. And how to know when I will receive a letter from HMRC for Class 2 payments? I worked in UK immediately before going abroad in 2019 and since then I work abroad. Do I need to contact HMRC now, or wait another couple of month for Class 2 letter to be delivered? I have to pay for the year 2019/2020 till 5 April 2026, so I am not in hurry yet, but I want to make all 5 remaining Class 2 payments before 5 April 2025. Thank you.

Hi,
The department who will process your letter that you returned to HMRC on 22 May 2024, are currently processing post received on 28 April 2024.
You can expect to receive a reply to your letter by 21 September 2024.
Please note this date is an estimate and may change. If you haven’t received a reply by that date, please contact HMRC for an update on your application.
The contact number is +44 (0) 191 2037010.
Lines are open from 8am to 6pm, Monday to Friday.
Thank you.