White screen, TFT LCD 2.8" from China

Hello I'm new in this forum and as well in the world of Arduino. I have a little knowledge about Arduino programming and other programming stuff. But now I've bought a little 2.8" LCD Display from banggood.com:


And my problem is, that the screen looks all time white. For a few minutes, the screen showed the wished letters. But after re uploading sadly the screen shows again white.

Maybe this other's informations can help.

I've a Geekcreit Mega 2560 (fake Arduino, but other processes work as fine)

A shield: http://www.banggood.com/CTE-TFT-LCD-SD-Card-Shield-For-Arduino-MEGA2560-With-5V-To-3_3V-Level-Translation-IC-p-1080424.html?rmmds=search

I don't know why. Can you help me?

Thank you!