Hi ker40 donn,
If you can not get in touch with the National Insurance helpline or the Future Pension Centre, you can complete a call back request form on the gov.uk
You can complete this form if you're struggling to contact the Department for Work and Pensions (DWP) by phone to pay voluntary National Insurance Contributions.
DWP will contact you on the phone number you provide in this form to discuss payment of voluntary National Insurance contributions.
If you submit a request by the 5 April 2025 deadline, you will still be able to pay voluntary National Insurance contributions after the deadline has passed.
If you have already requested a call back, please do not send another request.
You can fill in the form following this link
Request a call back to pay voluntary National Insurance contributions
You can also contact an adviser through our webchat service ‘ask HMRC online’ following this link
Ask HMRC online
Thank you.