Voluntary NI Contribution while residing abroad

Dear HMRC I sent a letter and emails in June this year and included form CF83 asking for options to make up gaps in my contributions. I have been living in the US for the past few decades and understand it is possible to make appropriate contributions. Could you please confirm options and contact so that I can get a response? For security I have not included personal details like NI number, etc.

Hi pardeep panesar,

Unfortunately we cannot give specific advice via this Forum.  
I can confirm though that our International Caseworker Team that would deal with your CF83 application is currently working on applications received from Sept 22.  
I am sorry that you have therefore not received a response yet, your patience is appreciated as we work through our backlogs, you will not be penalised for our delay.
If you need to discuss your application our NI Helpline is open Monday to Friday from 8am – 6pm on +44 191 2037010.

Thank you.