So the original support worker just pulled 20% (and then 5%) out of thin air? Given your internal knowledge, can you maybe explain why a support worker would ever do that if policy is simply to forgive the debt?
Anything Netlify deems them to be, of course. That's why these sorts of T&Cs use weasel words like "legitimate", "reasonable", "expected", etc., instead of giving specifics you can action against. That way they can claim every thing they've done is legitimate and reasonable no matter how fallacious that claim is, and double-dog dare you to spend the time/money to take them to court (or worse, imposed arbitration with an arbiter of their choice) and prove them wrong.