I suspected employees might get bored of taunting the AI, or the novelty has worn off.

Also, is anyone actually paying for this stuff? If not, it's a bad experiment because people won't treat it the same – no one actually wants to buy a tungsten cube, garbage in garbage out. If they are charging, why? No one wants to buy things in a company with free snacks and regular hand outs of merch, so it's likely a bad experiment because people will be behaving very differently, needing to get some experience for their money rather than just the can of drink they could get for free, or their pricing tolerance will be very different.

I've personally also never used a vending machine where contacting the owner is an option.

I'd like to see a version of this where an AI runs the vending machine in a busy public place, and needs to choose appropriate products and prices for a real audience.