Voluntary Class 3 amount for april 2023- april 2024

I live abroad and last year applied to pay voluntary class 3 contributions. Today I received a letter asking me for 685.50 for the year April2023- April 2024 The reason I am confused is because of the amount - when I look back at previous years the amount is 824 pounds for a full missing year. Why is the amount for this most recent year lower? I am concerned because I made two voluntary bank transfers for previous years of much smaller amounts for 2 years where I had worked in the UK and only had to pay back for a few weeks, and I sent a letter by post explaining which years they were for, and now I'm wondering if someone has just reduced the amount for the most recent year which was not what I had planned? I was assured that they would allocate the money I sent via bank transfer to the correct years. Yet they still show as unpaid. It is very difficult to me to call from abroad - I always end up in a long queue and rarely get through, and the phone call costs me 20-40 euros each time. Thanks for any help!

Can delete this post, I was able to fix the problem over the phone already Thank you (The amount is meant to be 907.40)

Hi,

May I ask that you either call our National Insurance team or write to us as we will need to check your National Insurance account.  

National Insurance: general enquiries

Our postal address is:

HM Revenue & Customs
PT Operations North East England
BX9 1AN
United Kingdom

Please include your full name, National Insurance Number, address and your query to ask us to check the payments of contributions that you’ve made and the correct amount required for the 2023-2024 tax year.

Thank you.