When you agree to participate in a bounty campaign, you agree to its rules. And the rules are always spelled out that the organizer can change the conditions for participation in the campaign at any time at their discretion.
This is a free world and everyone should take care of themselves and should not expect any organisation to interfere so that we can fight for justice. The maximum we can do here is, opening a scam accusation against the owner/dev/bounty manager and then demanding for compensation. In meantime we may go for negging so that other people will be cautious against them.
Just make 100 researches before you join in campaign.
To make sure that we are working safe, we must go for our own due digilliance so that we can prevent unnecessary hassles later on. Most people are failing on this and later blaming on others for their mistakes. Scammers are everywhere hence in the forum too in the name of ICOs.