Bad service at russel

My sister bought a phone on the 4th of August, they didn't want to open and check the phone cause it was late so they said she can open it a home because she waited for long she was tired and hungry so she agreed when she got home she opened the phone only to find out it has a thin line right inside the LCD ,she took it back the next day and they apologized and said she will get a new phone after 2 weeks,a month passed she called them they said it by the repairs she must wait another 14days,she called them went there alwys stories it been almost 4months full they saying they cannot refund her no give her a new phone ,she must wait until they get stock of which they nit sure when.