New York State Disability law

my co-workers and i recently purchased additional new york state disability insurance through our employer that is completely paid for by the employee. it was marketed with a l4 day elimination period and payment of a percentage of salary. when several employees attempted to collect, the carrier refused to pay based on the fact that the employees were still receiving sick pay from the employer. when they noted that they weren't informed of this prior to purchase, they were told that it is new york state law that there has to be a 20% loss of income before supplement benefits can be paid. what recourse do we have?