I seriously doubt that, only a small % of SR users send all their comms encrypted and unless the vendor clearly states on their vendor page that they will not respond to any un-encrypted messages they are probably just ignoring you or haven't gotten around to responding yet, if they are a big vendor it can take a few days for them to respond. In sying that you should encrypt all sensitive and identifiable information, I see someone has kindly posted you step by step instructions on how to instal PGP.