Macro has faulty Defy fridges

My mom bought a Defy fridge from Macro Carnival in 2016, before six months was up it broke and Defy was contacted and they sent a technician to come fix it. The fridge broke again and a defy technician was sent again and they said the fan had broken. So they could not fix it because they were out of stock with their fans. My mom decided that she want the fridge anymore so they said they will not refund her but give her another fridge.

Fast forward in 2017 the new Defy fridge is broken and they sent their technician again who said the fridge had a problem with the fan and it was fixed. now in 2018 the fridge is broken again and they sent their technician who said the fan has broken down again. My mom is sick and tired of driving to Macro to complain about the fridge and finally when we got the Defy service consultants to tell we cant deal with this fridge issue anymore they said we need to deal with the Macro store manager for a refund. The store manager refuses to refund my mom saying that 6 months has passed. My question to Macro and Defy is it fare to buy an appliance that is suppose to be new but requires repairs every now and again? I would like the store to give us his own personal fridge and take this one and lets see if he would enjoy the kind of heart ache he is putting us through?