Pension Back Payments

[UBear]

I have seen this asked before, but not quite the same way so forgive the questions if it is a repeated question.
I`m up to about 90months and would like to get it closer to 120 for more options.

For background, I worked at one company for 6 years that did not pay into any pension schemes as I was technically a "part timer" even though more than full time.

Anotherr company 10 years ago that I worked at for 2 years that gave pay slips to say they paid into the system, but it appears I have no credit for this with the current pension update. I left for work overseas for 2 years respectively between these jobs and returned.

I have been back now for about 8-9 years and have been paying as an employee for 3 years and self employed for 5 years.

My questions are:

a) Can I back pay 2 arbitrary years worth of pension, or does it have to be 2 years that were unpaid in a certain time frame?
b) I found a pay slip from the company of 10 years ago that showed they were supposable paying, but it is just small company A5 print, no official stamp. And knowing that previous company, I suspect that was purposeful. This is between 2007-2009! Can that be back claimed?

[RetireJapan]

I would go and talk to the pension office (not the desk at city hall) or call the national phoneline. As for payments from your previous company, that wouldn't be backpaying but rather fixing your pension records.