Shockingly Poor Service from Hifi Corporation Northgate

I bought a dishwasher from their Northgate store which mul****ion within a week of purchase and they took the NEW dishwasher for repairs and it is a month now they have not returned the machine..The lack of service seems to be the norm as their Manager don't even care, let alone an apology or follow.. Utterly disgusting service from Hifi Northgate