Vet not being paid for treatments

I'm having a really frustrating issue where the pet owners won't pay my vet for treating their pet. It could just be me not knowing how to make them do that but I'm really confused.

After my vet successfully treats a pet, the owner just stands around idly with a simoleon symbol above their head. My vet can't do anything except a few limited interactions or dismiss them. Dismissing them just kicks them out and they don't cough up the cash. I can click on the pet and select Bill Owner but the actions immediately cancels itself every time.

What's going on here? How does my vet get paid for treating her patients? I have no mods or CC in my game. I always remove it all before updates and add-on installs and don't put it back in until it's all been updated for the latest content.

 

I ended up starting over (not just because of that glitch, I wanted to start out with a different strategy) and now her vet clinic runs pretty smoothly. The pet owners pay as soon as she finishes treating their pets. She doesn't have to do anything to make them pay the vet bill. I hope starting over isn't the only solution for that, though, because that would be awful for players who were really attached to their files.