This game is pretty interesting and fun. I hope the creator is working on the bug fixes though. It seems like the game is doing the "check if player has $500>take $500" twice in a row, double charging us for 1 week. My guess is based on this exact text from the game.
"Vacation extension due. You've payed $500 dollars for a longer stay.Vacation extension due. You don't have enough money. Your vacation is at an end."
Because the second "Vacation extension due" doesn't have a space between the last sentence, that makes me think the check for enough money is happening twice.
Or, I could be an idiot and it's an entirely different issue. Still, hope this helps.