The vendor is smart and is counseled by a smart lawyer.
His payment is blocked and he has decided to take the matter to its logical conclusion.
It also shows that all efforts of the vendor to realize his monies, amicably have failed.
It is better to make the payment and close the matter.
The employees of the company designated as authorized to deal with vendor, communicate with vendor.
On the strength of the communications the vendor might have decided to include the employees in the list of notices.
The employees may download the communications from Top Officials, Directors, MD and Board etc deciding to block the payment and keep it safely, for their defense.
Once the matter is in court it has to be contested in court.
Therefore approach a competent lawyer with all records and docs.
The employees should defend their interest in the best possible manner.