I'd talk to the router/ISP/network provider next. This does not sound like a TV problem but something the network can't handle. Be sure to check the make of the router and such as few of those are Samsung.
I have a Samsung UE39F5300 smart tv that is connected via ethernet to my sky hub and recently upgraded my phone to an xperia z. Now all was good with both devices until about a week ago I could not seem to get wifi on my phone. to cut a long story short the moment the tv is turned on and connected to internet my wifi on my phone stops despite still being connected.
All other phones still work including another model xperia and i'm not aware of any updates that may have caused the confliction.
Any help would be greatly appreciated