Game store gateway

Bought two hisense 55inch uhd 4k smart tv from game gateway, at time of sale the sales rep advised if any issues the can replace or credit the tv. Almost a month of useing the tv one of them ended up a white line at the top, bottom and both sides of the screen.Contacted game via telephone spoke to Rowen who advised it will take 10 working days to have the tv looked at i then asked to speak to a manager and was told there is no manager avail and he will get the manager to call me back till date no manger called me back. I then contacted the on facebook messenger and qas asked for some info which i did send and this qas last week in which they rep**** yesterday that they will have a hisense tech to contact me to come check the tv. Today the hisense tec comes out looks at the screen and says it is normal the guy that comes with the tec says he cannot see the white line that both myself and the other tec can see. So it seems tha after paying alot of money hisense regards the white line around the screen as normal and as for game gateway jus passes their customers over to the brand supplier and it out if their hands it shows how game gateway take care of their customers.