Employee Incentive suddenly cancelled

We were informed that if an employee will not avail even 1 day out of our 15 days Sick Leave benefits for a year, they will be entitled to receive 10k worth of gift check at year end. This have been the policy for let us say 5yrs now, until last year 2012, the management then decided to cancel this incentive just like that. No alternative given, no option to replace the said amount. This is in cost of employees trying to go to work even if they are really sick, desperately aiming for the said incentive. Not to mention that the 15 days SL priviledge is not convertible to cash unlike other companies that are paying the days of unused SL. can the management really do that to their people? i hope for an immediate reply...

you can file a complaint at dole and argue that it is a diminution of benefits