Plugin Help ChestShop issue! "Shop owner doesn't have enough money."

I am pretty sure it's ChestShop because I've tried a few economy plugins already, but every now and then the server shop will say "Shop owner doesn't have enough money."

I can fix this by restarting the server, but that's very silly to do, especially when one hopes to have a big player base one day, rebooting to fix a single plugin doesn't seem logical.

I've read up on this topic which was brought up on many forums in many places over the internet, and no one seems to have a solution. There are some who say "UUID version update" caused the issue, but I've not updated this plugin, it's been the same version since I've been designing this server. Also someone said in another forum they were booted while AFK trying to sell. ChestShop doesn't work while AFK as far as I can tell, and one needs to re-log in order to exchange again if they tried trading while AFK.

I am on 1.8 Spigot, but this problem has persisted since 1.7.9 for sure. I'm tired of dealing with it, and would like either someone who knows explain what it is and how to fix it, OR I would prefer another shop plugin that is on par (with scaling stacks, best feature) of ChestShop.

Thank you very much!