health insurance and pension

I am a foreign resident in Japan with a five year visa.

Due to the corona virus situation I had to leave Japan urgently, and cannot return for quite a few months.

When I was departing I was not aware that I wouldn't be able to return for some time, so I did not notify my city office and cancel my National Health Insurance and Pension before doing this.

My questions are these:
1. Is it possible to cancel these by post or over the phone?
2. When I return to Japan in the future, would I be able to show the City Office that I've been out of the country for a number of months - and would they erase my NHI and pension bills for these months? Or would I still have to pay all of those missed?

It is very unfortunate that you cannot return; I assume your employment contract is still in effect? If you are still on their payroll of an employer in Japan, meaning you are still registered as a resident in Japan, I don�ft think you can cancel out of social security schemes. There should be a way to have the payment obligation reduced/waived due to lower income, though.

Thanks for your answer. No, my employment contract is not still in effect.