Bit confused regarding how long you have had it. You say 6 months and then say Dec. 12, 2015, which is only 4 months. Either way your tablet should be covered by the manufacturer's warranty unless it has been damaged by you. (1 year for parts , but only 90 days for labour costs, which unfortunately for you, has now expired). So to get it fixed it seems that you will have to pay the labour costs, unless you can convince them otherwise.
Here is an image, taken from the User Guide, which details the warranty provisions for your tablet.
Here is an image taken from the User Guide for an Envizen EM63 that shows what you have to do to get warranty service for your tablet.
Here is a link the the User Guide that it came from.
Hopefully this is of some help.