What is the procedure followed in your organization regarding the receipt and dispatch of mail?
Will they affix any stamp to acknowledge the receipt of any letter?
If so, please prepare a letter stating that, I worked in your organization from _______ to _________ as __________. I served the notice period from ______ to ______. I have handed over my responsibilities to my successor, Mr. ___________, on _________, which has been clearly explained to my then in-charge, Mr. __________. During my tenure, I have served to the satisfaction of my superiors/seniors, been regular to the office, and there have been no complaints raised against me. You are requested to issue a Service Certificate / Experience Certificate to that effect so that I can continue my career journey.
You are further requested to acknowledge the letter as received, and if there are any deviations in the above details, please convey them to me within 7 days of receiving the letter. Failing to do so, I can use this acknowledged letter as my service certificate until you issue my Service / Experience Certificate.
If you successfully receive acknowledgment for this letter and hand it over to the HR Department, they will have to issue you the Service Certificate / Experience Certificate without further delay.
Please give it a try like this and confirm the further progress.
Good luck