First of all, you need to be firm here. You were told by your boss that you could work from home, and you did work from home. That cannot be interpreted as a vacation day, period. Did your boss notify you that you could work from home via email? If so, good. If not, that’s still ok. Just be completely confident that they will correct this and return your vacation days. Email your boss and tell him that payroll made a mistake and toook 2 vacation days from you. Ask him if who the best person is to contact to correct the mistake. If he pushes back, be calm and consistent. Either forward him the email where he told you that you could work from home or remind him of the discussion you had and how you worked from home answering phone calls. Then be clear that you are not asking for vacation days back. You’re just trying to figure out the easiest way for your vacation days to be correctly returned. At this point, if he is not cooperating, forward the thread to HR and request a meeting. If he refuses to communicate via email and prefers to talk in person, remember to be firm and calm. If he insists that you will not get them back or makes you uncomfortable, demand that the conversation be had with HR present. This is wage theft.