So if I am understanding this right, its not just failing to feed BBs, but rather now when you pull the trigger, nothing whatsoever is happening?
If you have fully charged the battery, and tried again with no luck (ensuring that you haven't somehow forced a tamiya connector together reversing the polarity of the battery with the wiring of the gun ), then given that it is new, I would be inclined to return it to the shop for a refund.
Are you using the battery that came with it? Ideally before you return it, try to use another known good battery. The batteries that come bundled with some guns are often sold as 'free gifts', so there is a small risk that if you return it to the seller and upon testing it turns out that it is just the bundled battery that is dead, they might try it on with you and charge you for the return postage (albeit, that would be a little rough in my view).
If it isn't something as simple as the battery, then opening it up and attempting a fix will likely render the warranty void, so its not something that would seem to be worth doing.
