Makro Strubensvalley has POOR service

Makro Strubensvalley has poor service , we bought Samsung ST408 sound tower in April, the box went fautly (frezzes ) and has been handed in for repairs 4 times and are insisting the box is fine , however booking notes shows its frezzes and we have show the staff onsite but the manufacture doesnt want to take accountability of the faulty box ....Makro is also pushing back in refunding us the equipment.