I d'no how yall do it in Canada but in the U.S., that would usually mean 1 of a couple things:

1. You were robbed.
2. You's about to get robbed.
3. Your place was just bugged.

That's usually the case when unmarked vehicles come to do things in your home out of nowhere. Do you rent? Because then it's completely possible that your landlord requested someone visit. Do all your research first before making any rash moves.