Disgusting Deli food - past sell by Date

I bought Buffalo wings at Aspen Spar Port Elizabeth just after 19:00 the evening because I had already had bad experiences with their prepared food I bought it regardless... First my children started to complain I then got an awful smell much like sewerage the chicken was off, probably past sell by date prepared in heavy sauces and resold to patrons.. My concern is my children and I ate it and should I fall I'll Spar will be liable