a special smart contract was deployed and everyone who wanted to receive a reward did it with its help
Thus, after the end of the bounty campaign, you introduced a new rules, one of which implied the need to spend ETH in order to receive tokens.
For example here
https://bitcointalk.org/index.php?topic=2016468.msg23687427#msg23687427wasted 0.077527716 ETH
I think that you just hope everyone forgot about the unpaid bounty.