The arts and crafts chain Michaels (https://www.michaels.ca) has a variety of boxes and frames. However, you will have to figure out mounting / spacing / backing fabric or images yourself - it's not a turnkey solution.
There is a group on FB called Canadian Veteran Marketplace; you might be able to find someone local on there to make a nice custom one. I've seen a few of them showcased.
I have the box linked below (or one very similar one) from Michaels, not used for medals specifically and it is okay. I used it for a shadow box for my "PRes days" stuff so it has things like command badges, cap badge, collar dogs etc mounted in it. I'd add a pic but...it's in storage right now as I'm waiting to move into a new place. There's a back board that might work for attaching medals to.
That's nice; I had overlooked that option. I had my medals court-mounted as I was with our ceremonial unit, but now that I'm no longer in that gig I could do as you have. Hmmm, I wonder if I could still find the certificate. I've had a couple of 'three dimensional' items professionally framed and it's all in the creative use of the matting.