If short trade is not an option then you should do long trades and hold instead, you should also consider that some of those coins might be pumping for now but in the long run they will collapse someday you might even see those coins getting delisted to that exchange, if you've done deep research to those cryptos then you can safely assume that they are good for long-term goals and profit, lastly consider a decent exchange if you are not confident to the recent one.
I think that most of the users of crypto currency are insecure in today's day, since practically all the coins for today do not have real value. Perhaps if the market begins to recover, then we will return the figures for early 2018.