1 day old qn90c 43 usage mode has decided to grey itself out and i cant get it back

[Live1]

Got new tv today I just unboxed it and was excited to see the quality so went to the retail mode it asked for a pin I entered it then my phone rang so backed out of the setting to go and do it later,so after the phone call I go back to the usage mode setting but this time its greyed out,my tv has not updated or anything as it is not linked to the internet, I factory reset it 10 times and still I cannot get this setting back it's still greyed out ,I'm probably going to return it tommrow because this isn't normal the setting should not suddenly lock you out of them for no reason ,anyone got any insite on this?how do I get the usage mode to not be greyed out?,like I said it was not greyed out at first and my other Samsung tvs are not greyed out 

[sundaebb]

If it's greyed out and says Usage Mode - Home Mode you're good to go. It's already in the mode you want.

If not you can change it via the service menu but I'm not sure if you're allowed to detail the steps on here.

[Ginga_p]

Where did you buy it

[Live1]

From the shop brand new sealed I'm returing it because of this fault 

[Live1]

How can I change it so the usage mode is back to working again pm me if you cant say here or just say here I do no how to get to the service menu but I cannot see how to make usage mode available again like it was,nothing should be greyed out in my new tv that was once working 5 min before

[Live1]

The tvs software must  be defective so I'm sending it back for a refund as no1 here or Samsung phone support can help 

[Ginga_p]

What shop

[Live1]

The shop is irrelevant unless you can help get the settings back working 

[Gurky]

It won't let you change the usage mode with any apps open.

[Ginga_p]

Sounds like there is more to this story than you are divulging