gas tank sensor

friends I bought the new 1.6 xs, the indicators of the vehicle are working well, but how do we change the problem at the warehouse?

I am full of the warehouse, no problem, it is full but it shows half tank when it is finished. :) I do not say that the fulle will be fixed to the owner before me, but I am traveling with an additional warehouse.

The buoy may not be defective in the warehouse.

I know that I have a buoy. There was something like a black box on the arm end, I saw it while cleaning the tank

So how do we get it fixed, so is it possible to repair it?