Of course not.
This case is NOT about the terms, but the very underhanded way the casino's back end systems carried WR from earlier deposits, something that was key to their argument as to how the player had broken the terms.
I believe the casino have acted in bad faith here, knowing that their systems have failed to properly handle the WR carry over in this case, but also knowing they can rely on the terms to support their action, and that there is no way to prove one way or the other who is right about the pop up and other presentations at the point of withdrawal.
The only way to settle this would be to recreate the situation the OP faced, and then record via screenshots how the cashier handles an attempt to withdraw.
The rep has also dodged an important question, and that is whether it is PURELY the carry over that created this situation, with the player having fully met the WR that would have applied to a deposit of 500 with a 100 bonus. It is key because not only does it clarify whether the player met the WR he KNEW would apply, but because if it was solely down to the carry over, it is possible that he DID see a misleading pop-up during withdrawal because the system was only looking at the WR for the 100 bonus, rather than any carried forward from before.
Casinos should be careful, because sometimes something they think can never be proven DOES get proven eventually, just ask Absolute Poker and their cheating spree that only got busted because of a silly screw-up made by a lowly CS agent who was not "in the loop", and so failed to ensure that the correct "doctored" logs were sent out, instead of the full logs.
See, here is where the player should be expected to apply some common sense.
If I received a popup when I attempted to withdraw saying "are you sure you want to withdraw? You will lose your bonus etc etc" I would immediately think "Why...maybe I didn't meet the WR?" and then contact support to find out what was going on. Amazingly, that is EXACTLY what the OP DID.....so actually the popup DID cause him to stop the withdrawal process right there. The HUGE and totally careless and ridiculous thing they did next was what created this whole issue....instead of WAITING for an answer from support, whom he contacted because he obviously strongly SUSPECTED he had not met the WR, he just became impatience and withdrew again anyway and completed the transaction which made his winnings disappear.
The OP would NOT have lost his winnings if he had:
1. Read the terms before play. (x3 chances)
2. Played his balance to zero OR under $1 before making another deposit/accepting another bonus (and he DID accept the bonus via a popup confirmation which ALSO lists the terms attached..he could have declined at this point) (x3 chances)
3. Checked his WR status via the software cashier section
4. Contacted support when he realised he may not have met WR and waited for a reply (he did contact but didn't wait)
5. Ceased any further action until he knew the exact position he was in
So, NINE opportunities to avoid losing his winnings. NINE.
When he received the "You will lose your bonus if you withdraw" popup, as I stated, he obviously thought he WOULD lose his winnings as well, otherwise he wouldn't have bothered to contact support. So, even if the popup said "and winnings", the OP STILL would have done exactly the same thing i.e. contact support. Considering he didn't bother waiting, one would assume he wouldn't have bothered waiting in that situation either, so the result would most likely have been the same.
The term is unreasonable, but the player accepted it. Three times in fact. The casino provided FOUR avenues to prevent the situation:
1. Written terms via the website
2. Written terms via the bonus accept/decline popup
3. WR counter in cashier
4. Live chat
The carry on by those who think players should be absolved of any and all responsibility for their actions seems to focus on the argument that there should have been a FIFTH avenue (a "lose winnings" popup...and we don't know for certain it DIDN't say that BTW). Really? Really??
The best resolution IMO here is for the casino to reset the players balance to his last deposit and bonus amount and clear all historical WR. IN this way, both parties are shouldering some responsibility for what happened.
If the casino just pays up, then any player in the past who had winnings confiscated (and there would be some I'm sure) would automatically have a claim. You can see why the casino would be loathe to do such a thing.
Interestingly, I see KK promotes them on this site, so they must be solid and reputable.