Maxent MX-42HPT51- will not respond!

Hello - We have had this set now for about 5 weeks. And after about 2-3 hours of watching the controls on the TV and the remote will not work. The only way to change channels it through the dish network remote but this does not help volume control, TV settings, and/or shutting TV off and on. You have to unplug the TV for about 10 seconds and then plug back in and then everything is operational again for the next few hours. This started happening within the first week we received the set. We though it may have just been a one time weird thing but now it happens more then not?

Any suggestions? Since the set is so new we should prob just bring back for an exchange or refund - unless someone may have a easy fix.

Thank you,