I am not clear whether the problems you describe are happening with the KK2 board or your own system.
Silly questions, but they need to be asked :
Are the motors turning in the right directions ?
Have you got the correct props fitted to match the motor directions ?
You do not say what altitude you are at, but increasing altitude, but not just 15 feet, will reduce the efficiency of the propellers but the quad should still fly. What motors are you using ? The surface on which the quad is resting should not affect its performance to the extent that it will not lift off.