Vespa — severe service and performance issues with my vespa

Recently purchased vehicle ( Brand new - Only 2 weeks old).
Vehicle is not moving properly from very next day on wards and also getting engine off while driving the vehicle.
Got a small accident also due to this issue, vehicle stopped suddenly while driving the same.
We have given the same vehicle for servicing almost two weeks before and not yet cleared this issue.

We are totally worried because of this issue and nobody is taking care for the same. Everybody is so casual in this regard.

Purchased vehicle from Jay Mootors, Cochin, Kerala