I wouldn't be surprised, there is hybridmixer (supposedly by same owner) who people report have scammed some people (the promotion reward was credited to liqui account, hence the connection)
Also, liqui exchange refuses to answer pretty basic question regarding interests and funds management. Combine everything togeather, and it all looks like a ponzi. (but i thought it will last longer due to low interest rate)
People affected by their unprofessional acting should open scam accusation imho.