I found a post on Medium from their co-founder Lewis Barber announcing Sharpe is ceasing operations on April 4th, 2019.
Can't tell if they were a scam, I can see a daily trading volume of $1k - $7k in the brief period they were on cmc. Every other mean of communications is also suspended: twitter, facebook, multiple telegram channels.
https://medium.com/@sharpecapital/sharpe-ceases-operations-4cb395d16f85It just completely died.
screenshot for illustrative purposes only, what a sudden death looks like

