This area is one of a lot of prior discussions. There are many reasons it can fail from distance, hardware failures to others. If you feel it's hardware, make that call and let them fix it.
They should walk you through the distance (under 20 foot since it's not as good as laptops, etc.) and more.
Bob
We have a UN55ES7100 and had no issues with connectivity and the SmartHub till three months ago. Every time we go to Amazon or any other app it says it cannot find any wireless connections. Our computers, phones and all other wireless devices have no issues connecting but the Samsung "Smart TV" never finds any available connections. We hooked up the wired connection and updated the Hub along with newest software and can connect through the wired connection but just not the wireless
Any ideas?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic