What would you do if your boarder did this? How much do you think it cost me?

Moldy food in plastic bag on pantry shelf. It stank and when I took it off it was all stuck to the shelf so badly that the shelf's lining ripped and it is all permanently stained. I thought about it and thought if I went to sell my place it would probably reduce thousands from the price because it looks so bad ($10 000?) and could cost $1 000 to fix it?