bonus terms changed after i opted in and support says current rules apply

ok so i get why sites want the current rules to always apply, i mean it keeps things clean if they mess up a promo description or whatever. but i actually screenshotted the original bonus terms before i played, and now they changed the rollover from 20x to 40x, way after i opted in. their support just tells me it’s the “latest terms only” even though i already started playing with the bonus under the old terms. isn’t that kind of shady? has anyone actually pushed back and gotten the original terms honored?