I don't know what is in your letter but mine had this "To submit your package outside of Canada: Please submit your package to the nearest Visa Application Centre along with the VAC Passport Transmission fee". There is a VAC office in my state so I mailed it it to them. They forwarded my docs on to IRCC via VFSThe email just said to submit my passport for the COPR. Since Indian passport holders have to submit their physical passports, I am not sure if I have to go and physically deposit it by taking an appointment/no appointment needed, or if I need to do the same via CVAC official courier service. The email didn't clarify these points.
Thanks for clarifying about the RPRF.
I spoke to a few people and they mentioned that RPRF and Biometrics do not have to be paid/done again.
Still confused about the entire process of passport submission.
Call your nearest CVAC and ask them