If this was a gratuitous payment then has the bank recovered the payment from those ex employees who were paid from the date of commencement of payment till such date that it was stopped? If the answer is in negative then a contract existed from the date date of commencement till the date on which the scheme was discontinued. As a corollary thereto, you can claim the arrears of this scheme. It is not worth taking any action unless the answer to the above question is in negative.