Plan is corrupted.. not sure how to go back to known good version

Hi 

Today, I was updating the project plan, using the desktop client. I checked-out the plan from the Project Web App and was updating the same. During the update, I kept getting "Do you want to save the plan?" messages and every time the message popped up, I kept clicking "Yes". 

Later I observed that the plan is totally messed up. The WBS is totally wrong and now i am not able to set it right. 

Please refer to the attached screenshot. 

The issue is that the plan on the web is corrupted too and now i don't know how to go back to the last known good version, so that i can restart from there, to update the plan.