Hi
That is strange, it shouldn't delete your save files then. Can you try clearing your Origin cache? It should check and restore all your game data after you've done that. When starting Origin again, do so by right-clicking and selecting Run as administrator.
If you are still unable to resume or start over, please reinstall your game. I won't be able to retrieve your save games afterwards since they seem to be gone, but you should be able to play again without issues.
Please let me know how that goes for you, or if you have further questions.
--Tom