When moving oversized items, make sure you look at your belongings before moving. This way when you assume damage was done to your items you can go back to what ever evidence you have and confirm if the damage was done by the movers or before that. When moving items like tables mirrors and big item like those there are a few things that must be done before moving them.
When moving tables take them apart if possible and wrap each part in thick cloth or anything that will give it suitable protection. Things like mirrors should be packed with cardboard box the same size as tha mirror on the front and back, so in case of impact it wont shatter. On top of the mirror place a blanket or anything you would assume is protective enough to protect your delicate item.