My tenants are telling me that they are noticing bugs in their apartment, more specifically in their beds. They want to break their lease because of this and have stopped paying rent. Can they do that?

The first thing to do is to look into it, determine what type of bugs you’re dealing with, and arrange for an extermination of the property.  It is the landlord’s responsibility to deal with any pest issue in a timely manner.  The tenant could file a T6 application where they could request to end the tenancy and/or an abatement of rent. The landlord would have to prove that they acted diligently.