Which type of National Insurance for non UK company for independent employment contract

Hi I'm under an independent contract from a non-UK company, with a fixed monthly rate. That company won't arrange to pay NI for me. Can anyone tell me which class of NI that I should pay for? I checked with a few accountants and with different answers. I sent a letter to PT Operations North East England, but still did not get any response. Can you please help? If anyone ever had the same situation, can you please give some advice, I would really appreciate it. Thank you

Hi,
You will need to discuss this with the National Insurance helpline regarding your work status.
If you are living in the UK you may be able to be classed as self employed with foreign income as your wage or you can pay voluntary national insurance. That is if there are no UK operations for your company and you live in the UK.
Working for yourself 
National Insurance: introduction: National Insurance classes 
If you are living outside of the UK you can apply to pay voluntary National Insurance overseas.
The process involved is in the NI38 booklet and the form to send in is a CF83.
Social Security abroad: NI38 
Number - 0300 200 3500
Overseas - +44 19 1203 7010
Fax - 0845 915 7800
Overseas Fax - +44 19 1225 7800
Open - Monday to Friday: 8am to 6pm - Closed on Saturdays, Sundays and Bank Holidays.
Web Address - www.hmrc.gov.uk/ni          
Thank you.