It depends on whether you are entitled to be paid by your employer. If you are entitled to pay from your employer you won't get a social welfare payment, and should chase him for it if he hasn't paid you, if you are not entitled from your employer then you should get a payment from the social welfare.
As a part-time worker you are entitled to holiday pay from your employer if you have worked 40 hours over the past five weeks ending on the public hoilday.