I don't think you can pull those proposals up again if they didn't go through. In the future, you can do 1 of 2 things.
1. After you write your proposal, but befor you click on the submit buttin, copy all the content. That way, once you submit the proposal and you don't see it listed or you don't get that notification that it went through, you can just paste the content you just copied.
2. Use Microsoft Word to create your proposal, Then just copy and paste in the cover page area. If it doesn't go through you still have it in Word.