Any sett-off of debts between a co-operative and another person within 180 days before the commencement of the co-operative's winding-up and which has had the effect of preferring such person as creditor above another creditor of the co-operative may on application by the liquidator be declared void by a competent court if at the time when such set-off was effected the liabilities of the co-operative exceeded the value of its assets, unless such person proves that the debts which were set off arose in the ordinary course of business between him or her and the co-operative.