Does the rpm rise and the car actually revs but doesn't do anything? Like seemingly as if the car is in neutral and you're pressing on the gas pedal (but obviously the car is in a gear)?
I think Xulfiqar sb would be the best person to consult on this. But if the above condition is true, then I would also be more inclined towards a clutch issue. However, the interesting thing is that this happened after the service. It could be a mere coincidence too - but still gotta probe it from that angle. Again, Xulfiqar bhai is your best bet
Good luck!
Sent from my HTC Sensation XE with Beats Audio Z715e using PW Forums mobile app