Plumbing bill

[Mooko King]

Here's the situation, my tenant in my condo property claimed there was water leaking in the ceiling above the shower.  Immediately I contacted the condo owner upstairs and told him to look into this issue asap.  He called the condo building's management company who sent out a plumber to take a look.  They find that there was no leak at all and the ceiling was bone dry with no signs of water damage.  They find that the water on the ceiling was either due to the moisture/humidity from taking a shower or from just water splashing.  The management company then sends me the plumbing bill for the service request because there was no issue at all.  I feel like I need to re-bill this to the tenant since she made an unnecessary service request and that I shouldn't have to pay for it.  The unit owner from upstairs talked to the tenant and said that the tenant claims her son splashed water on the ceiling was apologetic about it.  What should I do?