Dear member,
How many employees work in your company? If not a supervisor, then to whom else could you have submitted your letter of resignation? To whom does this supervisor report? Did you approach the superior authority of the supervisor? If yes, what did he/she say?
I recommend handing over a photocopy of the letter from the supervisor, along with the original copy of the resignation letter, to the HR Department. Inform them that routing all applications through the supervisor is just an office protocol, and the supervisor does not have the authority to reject the application.
If the HR professional also refuses to accept the letter of resignation, inform them that you will be compelled to send the letter via Speed Post. The resignation date will remain valid.
Thanks,
Dinesh Divekar