Hashnest was formed by Bitmain but they sold them.
This should have been an immediate red flag, but I am sure even after realising this investors could do nothing to salvage the rest of the assets spent on mining contracts there.
Cloud mining sites are always going to scam its investors, this is a fact and this should be understood by every user here. Whether someone supports them or not, is a personal choice, does not mean that the project is going to turn legit.
Is there any way to force them to pay back the money they took from us?
If the people behind the scam can be identified. But let me remind you that this is not the first cloud mining scam and very few have actually been caught in real after extensive legal work.
Be careful of fake people trying to collect money in the name of legal proceedings for this scam - they might themselves be scamming you. Only do this if the group is known to you in real life. This type of "scamming the scammed person" scam has also been common among the victims of cloud mining scams.