Perhaps you need a TOS that requires a usage fee be mailed to a PO Box that has a reasonable "free" limit of like 100$ and when they exceed it, you automatically mail them a copy of the TOS, the logs and an invoice.
Just make sure you have a good lawyer.
is there a law they’re breaking?
because idk i could be wrong but some small project vs a 2.5T market cap company is gonna need more than “a good lawyer”
It would fall under contact law, and the case would hinge on either the ToS is binding, and whether the bot operator is deemed to have accepted the ToS, and whether access inflicts a cost.
In the UK, you would likely win in court, and be awarded £1 for your increased hosting costs. There isn't the concept of punitive damages for contract law here. YMMV.
However. People report that you can get paid by sending a plausible invoice to a tech company. The culture disincentivises verifying purchase orders.
Edit: oops, double-posted.