You have posted in the wrong forum.
The post should be in "Android Tablets" Forum.
http/www.tomsguide.com/forum/forum-107.html
That said, and for the sake of time (and to not make you recreate the thread) It sounds like the display was damaged. However, have they tried turning it off and then back on to see if the ghosting resolves? Sometimes that is all you need to do.
If that doesn't help, and you don't feel comfortable doing the repair work yourself, then a repair tech or manufacturer repair center will be best. Unless it is under warranty still, then definitely contact the manufacturer. As to cost, there is no way to estimate that. They are different all over the world.