NI Class 2 Overseas - payment not allocated

Hi, Applied around January 2023 to make voluntary Class 2 contributions along with a letter outlining the years I wanted to pay and enclosed a cheque for 12 years payments with the application which was cashed around March 2023. Received a letter in March 2024 confirming application to pay NI Class 2 had been approved and a breakdown of the costs. The total was very slightly more than the cheque I sent as I had not accounted for 53 week years where NI was due. In March 2024 I phoned the HMRC helpline to ask if they could allocate the payment made in March 2023 to the outstanding years. They could see the money was received but were unable to allocate it and said they would contact an international caseworker to do so and it would take up to 4 months. Since then the year end figures for 2023/24 came in and I noted that 2023/34 was now showing as full year on my NI record but the original cheque had not included payment for 2024/24. The 12 years I purchased still had not had payment allocated to them and are still showing as year not full. As the cheque had not included money for 2023/24 I made a BACS transfer in May 2024 for the 2023/24 tax year plus the slight underpayment from the 12 year original period. How much longer will it take and how can I chase it up? The cheque was cashed almost 18 months ago and it’s now almost 6 months since I last requested the payment to be allocated against specific years. I have been patient as I understand the service has been overwhelmed with applications but I would like this to be resolved. Thank you in anticipation.

Hi Genes,
You will need to speak to an advisor on the National Insurance helpline and ask them to update you with the current position on your allocation of payments.
The number to call is 0300 200 2500 or +44 191 2037010 if you are calling from abroad. Lines are open from 8am to 6pm Monday to Friday.
National Insurance: general enquiries
Thank you.