I was contacted by Exchantra / exchantra.com through social media. They promised guaranteed returns of 20-30% monthly. Being naive, I invested. The "account manager" pressured me to invest more and more. When I finally tried to take profit, my account was frozen and they stopped responding. Classic Ponzi/advance fee fraud.
Pros: Initially responsive customer service
Cons: Lost entire investment|Reported to authorities|Unresponsive