Replying to Shop won't remount bindings on my skis, say they require 7mm away from old holes. Is this legit?

Brought in a pair of Line Blends I bought used from a friend to get mounted. I had an old pair of Armada skis that still worked but were in rough shape. I wanted to switch the bindings from the Armadas to the Blends. The Blends had been mounted once previously, so there were holes in the skis. The holes were plugged properly. The shop took off the bindings from my Armadas, only to realize the bindings needed some new parts. $70 later they went to mount the Blends and after two days with no call I called them and they said they cannot mount the bindings because there is no mounting point that is 7mm away from any previously drilled holes. I've never heard this 7mm rule before or any number for that matter. I've heard don't reuse the same holes, but never that you have to be a certain distance away from the old ones. So now I have two unmounted skis and shop fees to pay.

I'm upset about the whole experience from the shop, but moving forward I'm curious if anyone knows if I can bring them to a different shop / have a buddy mount them or whatever. Is their rule legit? Do I just need to find a better shop? Can I still mount these skis without much risk?

Any help is appreciated, thanks.