What happens if a landlord vandalized the rental unit you live in?

You didn't explain what you meant by vandalized. A Landlord in Canada has the right to give their renter 24 hours notice that they will be coming to inspect the interior of the suite or home (good idea!) Smart Landlords take pictures or video tape the condition of the rental they have in case this should go into small debts court. It's "before and after." If a Landlord knows there is a pipe leaking in your suite they DO NOT have to give you 24 hours, but do need to contact you to let you know why they entered your premises. If a Landlord came in to ruin your furniture or personal possessions then you must catch him in the act or you do not have a leg to stand on. Even if another renter saw him entering your suite this is considered "hearsay evidence." Phone your Insurance company and see if you are covered for any damage and start looking for another place to live.