Everyone that joins ICOs, bounties or airdrops might recently be receiving some emails purported to be from a project administrators informing you of that your earlier contact of the support has been escalated and you need to be a certain sum of bitcoin or ethereum in order to abade the problem otherwise, you lose your investment or earnings.
It is a scam. Beware!!!
One of the reasons for origination of such scam oriented spam is the bounty managers openly displaying users email address on the bounty spreadsheet. Email are a bit matter of privacy and as bounty is an important task, people tends to provide their primary email of use rather than the one used for secondary uses.