I don't get any signal on the load, what am I missing? Shouldn't it amplify the input signal?
I have 50mA from the current mirror, the Vbe on Q10 and Q11 is around 0.75v
As Chris says in comments, you should be able to solve this yourself by probing different nodes and seeing where their behavior is not what you expect.
In particular, check if all the transistors are biased into the correct mode of operation.
The capacitors C12 & C13 are blocking the base currents. Add a 10K resistor from each input transistor's (Q10 & Q11) base to ground to allow a DC return path to ground.