You may want to raise this with the guests AND the Aibnb directly. You will probably need to have receipts to support your claim against their security deposit.
I have made it part of my House Rules that a loss of the keys carries on a specified penalty. This is probably a better approach, since you can claim that the guests have accepted your House Rules when booking with you, and that you are hence, entitled to a specific amount of refund.
The problem with lost keys, etc., is that you may be able to claim the actual out-of-pocket expenses but that your time, work, correspondence, etc. will remain uncompensated.
People are always more careful with other people's property if they know that they will have to pay for their negligence.
Danny