VFS Montreal: Required to submit additional documents requested in person?

Hi everyone, I had my French Schengen visa appointment at VFS Montreal on March 23. Today, I received an email requesting a missing original document (Attestation d'accueil). I live in Oshawa (5+ hours away) and have a 10-day deadline. My Question: Does VFS Montreal require you to return in person to drop off supplemental documents, or can they be sent via tracked courier (FedEx/UPS)? I’ve heard conflicting things from their helpline and I'm trying to avoid a 10-hour round trip if a courier is acceptable. My flight is on April 15th, so timing is tight with the long weekend. Has anyone specifically dealt with the Montreal office for a document "complement"? How did you submit it? Thanks!