NIC from abroad, paid for 10 years, only 6 showing

Good afternoon, I recently applied to pay voluntary NIC from abroad. I have been abroad since 2009 and haven't paid any NI since 2008. I received a letter stating I could pay class 2 contributions from 2013 until now since I had sent proof of employment abroad for that time. Class 2 payments are around 163 or 166 pounds per year. I calculated the total of those 10 years according to the letter and sent a payment with a reference for overseas payments. I recently checked and only the most recent 6 years are showing as paid and 4 are missing. Could you explain why that may be? And what if any action I should take now?

Hi Callum McCourt,

Unfortunately, without checking your personal records I am unable to confirm where your payment has been allocated to.
Please contact our helpline on +44 19 1203 7010 (lines are open from 8am to 6pm, Monday to Friday) to check if your payment can be allocated
to the years you intended them to be allocated to.

Thank you.