Caveat emptor
Though there may be some merit in the 'pump and dump' allegations, all investors who part with their money on the basis of gaining profits from selling at the right time in a fluctuating market are basically gambling.
If their due diligence is insufficient and/or market forces mean they lose money, yhat is the essence of gambling.
Resorting to litigation for losing a bet is a sign of either greed or they have little understanding of the system.