They should be considering the effect of this retraction of bonuses on long term employee morale. Is it worth it to take back a few hundred dollars given to employees when the error was on the part of the company? Is it also worth the publicity black eye they are now getting? They need to get their house in order.
The person(s) who calculated the bonuses might get fired-—but trying to claw back from everyone would be suicide.
The workers can find a hundred ways to GET EVEN.