The thing is, do you have proof that they changed it afterwards? I tried to use waybackmachine but there is no old version of the terms unfortunately.
Changing the terms after people having deposited would be a really shady move if it was true. Actually there are some sites I would expect doing something like this and NW definitely is one of them. Without proof though it's hard to chose a side in this one.
Yes. Here are the original terms:
https://i.imgur.com/sRd45TE.jpegAlso, in the Nitrowinner promotion thread, you can read posts by other bitcointalk members where they state that terms were changed from 20x to 50x. For example khaled0111's post:
https://bitcointalk.org/index.php?topic=5521825.msg64851706#msg64851706Seems like they are changing is just as they please. Definitely not a good look and some shady practice. I see you have posted in their ANN thread as well, hopefully the rep will reach out to you.
It's also a bit funky they include the deposit amount in the bonus rollover amount even though the rules clearly state:
"Bonus must be wagered 50x (

) before any associated winnings can be withdrawn" . Bonus is bonus, deposit is deposit, they are 2 different things.
Anyway, good thing you got a screen of the original rules. Let's see what their excuse will be.