Need Assistance

On the 26/02/2016 I purchased a fridge for my mom as a gift. It was delivered on the 29/02/2016 to her house. When she saw it, she immediately expressed her disappointment with the dimensions. I asked her to give it a try as i know it was smaller than her current fridge. After 3 days of use she noticed frost building up inside, which i must add is what her old fridge was doing. I called Game and spoke to Shane (Appliance Department Manager). I explained to him what my scenario was and he explained that all he could do was book an assessment for the fridge. I asked him, since it's still within 7 days am i not eligible for a full refund and he rep**** no. He said that once the fridge gets plugged in he can't take it back and i'll just have to deal with it. He also went on to remark that \who will buy the fridge now that it's opened?\". I asked if i'm not within my rights as a consumer to request a refund considering it's still within 7 days and he said the CPA doesn't apply to this scenario. I told him i don't want a cash refund as i will buy a bigger fridge from Game, i just need a credit and he said it's against their policy and i'll just have to keep the fridge. Is this right? "