Eeh,
1. If you mean a car and then go over a bump, it's a bug
2. If you mean that a car rammed you purposely, then report it here: https://truckersmp.com/reports Remember you need to have video evidence and the pinfo of the user. If you did not record next time I'd suggest that you did. Some recording softwares for example: PlaysTV, GeForce Experience (instant replay)