I believe it's both sides fault.
DuckDice.io - You need to make much more detailed explanation on how your bonus is functioning and how exactly you are counting wagers. With example on different % chance, what happens if you want to cancel, etc.
Player - when you accept a bonus, you need to understand and complain the bonus rules. You can't cancel it in the middle because you like your profit. Your profit is made with bonus funds.
Duckdice bonus rules:
Your balance will be locked while bonus is active. You can cancel the bonus at any time. Bonus must be wagered 55x to became a part of your balance.
1) He
can cancel in the middle!
2) His profit was
not made with bonus funds!