Maybe it's just me, but it's disturbing that you name an input pin outputA and outputB. I know it's the output on the encoder side, but it's an input on the Arduino (and code) side. But that's nit picking.
I think your main problem is in delays, whether they are caused by delay() or by the serial output. Encoders are working probably best in interrupt routines. During the delays, the state of the encoder pins might change.
void LeftTurn(int c) {
if ((-70<=c) && (c<=70)){
angle=angle+0.5;
servo.write(angle);
What does 70 mean here?