I hope I understood your question correctly.
Depending on your needs I suggest to create a branch line of the latest correct main line. Rename your old main line with all your latest developments. Download the main line again from the SPRNTR environment.
Override the corrupt main line by merging the branch line into the new main line. Then start from scratch. If you want, you can export some of your changes from the corrupt main line (renamed earlier) and import it into your (new) main line.
Use the correct deployment package from the Deployment Package Repository (SPRNTR) if you want to replace the version on Acceptance environment and or Production environment (button Deploy or button Transport to ...).