Tenant Lost Mailbox Keys Before I Could Get A Copy

[Art Maydan]

Good Morning Everyone,
I had a mailbox lock replaced while the tenant was home and the locksmith gave the tenant two sets of keys. It cost $95 for parts and labor. I came by later that day and he had already lost both keys. I asked the locksmith to put the keys under a plant but it's understandable that he'd give them to the tenant since he was home. Who's liable here? Do I ask the locksmith to come replace the lock again and put the keys where I asked him to this time? Or do I tell the tenant to pay the locksmith? I don't think this is something I should be paying for. At least not fully. And how can I hold whoever is liable accountable?

Thank you,

Art