Thanks for playing and leaving feedback! Without knowing more details I suspect this is more of a case of badly communicated set of features or not well balanced gameplay than a downright bug. I'm sorry the game doesn't currently do a better job of explaining it's mechanics and I hope to learn from feedback like this and improve the game based on it.
It depends on what they're complaining about exactly. If it's the surroundings then maybe there's trash around? Better furniture does indeed also improve their work quality. You can check the specific furniture bonuses when you expand the item in the furniture buying popup.
If the loyalty of the employee is low then they'd like a pay raise. Click the edit button next to their wage to change it.