Can I claim the chargeback fee my payment processor charged me?

Yes, and it is worth understanding why, because the reasoning generalises. When a guest's reversal causes your acquirer to debit a per-item chargeback fee, that fee is not a cost of doing business you absorbed voluntarily. It is a direct consequence of the guest's conduct, quantified precisely, on a statement you did not write. Courts are comfortable with that shape of loss because there is nothing to estimate. The amount is what the acquirer took, and the causal chain is a single link long.

The practical value is disproportionate to the money. A claim built from room revenue alone is one number the guest can argue about. A claim that includes a $25 fee documented on a third-party statement demonstrates that you are working from records rather than from a grievance, and it sets the tone for everything else on your one-page total. Bring the merchant statement page showing the debit, highlight the line, and list it separately from the room charge rather than folding it into a round figure. The same logic covers your court filing fee and service costs, which the prevailing party can generally recover, so keep those receipts too.