All Shop names Must match the DisplayNames.
You can do
"Medical": {
"DisplayName": "MedTender",
But the displayName and shop name must match.
"MedTender": {
"DisplayName": "MedTender",
Vortox, Thank You so Very much for helping on this. It is operational now. I will still have to go in and edit each vendor but half the battle was getting it up and running.
So, please correct me here if I am wrong but essentially what I got from this was that by me deleting the actual Medical (or renaming it) I should have just kept it and created a new "category" in which I willbe mindful of next time. Much appreciated Vortex,Thanks again
Also your first post you had Commands Selected as the default shop to open. Yet you had that shop disabled.
So you would have to change the default shop to open inside the config to one that is enabled.

On an Unrelated Note:
In the next GUIShop update, if you have all NPCs setup and no global shops you will have to have that string^ Blank ""
"Set Default Global Shop to open": "",
In order to disable the global shop and respond to the players with a new msg that will say global shops are disabled go find the npc vendors for when a player does /shop