Hello dear sir/ma, How best can one deal with a company that has not been paying pension and gratuity to staff even though they have spent all their lives to serve? Your response will be highly appreciated.

There is no law in Nigeria that mandates employers to pay gratuities. Except the company promised you in their employment letter and/or Employee Handbook.

You should rely more on contributions to Pencom. If they deducted from you monthly and didn't remit then you can contact Pencom to report them.