It looks like someone is trying to force dump the price. that doesn't help the credibility of your coin at all.
Welcome to a market economy. What can we do?
Actually devs can do a lot to suprvise their coin from these things.
You would rather own a coin that is manipulated by its devs rather than own/trade a coin that is completely free market and based on a scientific and mathematical proof of work?
I rather trade a coin that is managed well, and not every whale does whatever the hell he wants.
Those things make potential traders run away.