In a Warhammer world, this would be how greenskins communicate amongst one another. However, a Gretchen/Gobbo merchant would have some serious backup on retainer, something equivalent to a Nob or one of the larger MekBoyz who was actually making the gear and bullying the gretchen into selling it for him. Apologies for the 40k terminology but it has been over 7 years since I last got anywhere near fantasy Warhammer, much to my chagrin.
So yeah, in the back of the shop there is a MekBoy or Shaman/Witch Doc who has naturally kept the best gear for himself and can easily go toe to toe with the PCs. Have him knock them about a bit and then retire when they've had a sound beating. The natural power structure of orc survival is that you don't screw with those much stronger than you and the characters should be instinctively aware of this. There's a reason orcs grow throughout their entire lifespan and their kings in times of peace are often fairly long lived. Y'know comparatively.