[Q] Tab 3 problems topic

Hey guys

Recently i have a problem with my tablet those are :

The mobile data keeps turning off automaticlly ..
The brightness keep going up automaticlly without taping auto...
The screen brightness keep flickering and i dknt know why...
The tablet is very slow .

I have bought it before 1 month and i spent a lot of money with it...

Please help to sort this out please