Letter of Declaration of No-Break in Services (Continuous Services)
This document is used for pensioners, most commonly by government employees, for the revision of pensions or validation of services. It contains many details and is declared by the employee, which is supposed to be authorized by government officials and department authorities.
The best solution and option you have is to visit your nearest local Panchayat Bhawan or court premises, where you can find many "Documentation Service Providers" who have all the details and ready formats like the one you are looking for.
I have enclosed a sample format for you and hope it will work for you. However, I still request you to please go to a Documentation Service Provider for this.
Regards