Hello Bhushan,
you did not specify how is integration CRM - Genesys achieved. Do you use Gplus adapter or any other server-server integration, using ICI protocol?
If I assume standard ICI integration, then you be should be able to achieve the goal using:
1) implementing check in badi ORDER_SAVE - here, if the condition is not fulfilled, then raise DO_NOT_SAVE and the system will interrup save of the interaction record, which is triggered by End button, latest. I am not sure if VETO method is at right place to help you out.
AND
2) Implement OSS note 2144102 - End the Wrap Up only After a Successful Interaction
End. This note will synchronize CTI communication with interaction process, i.e. if the interaction process is not complete, the CTI is not commanded to end wrap-up mode.
We use this approach and it is quite reliable.
Regards,
Dawood.