How to rollback and override to a specific date within a Time Machine backup

my situation is kind of weird. I've totally crashed my system yesterday after installing bootcamp/windows 8.1 (bad partition format). Fortunately, I have a full backup Time Machine on a Drobo 5D (firewired). Since Drobo 5D need specific drivers to read data, I could not reinstalling the OS from Time Machine Backup. So I have reinstalled a fresh OSX El Capitan from scratch. After created the user and installing drobo drivers, I have bound the Drobo 5d Time Machine backup Disk to the Time Machine OSX service. I've done this because I though it was the way to do it... Error! When I went to restore, I have not seen my old data but just the new installation. When I go to directly within Drobo Backuped Disk, I see All Past Folders AND new Folders. I've tried to restore the backup user with migration tool App but no success, the same user as the fresh install, not the old one (with all my apps). Now I think I've corrupted my backup. Is there a way to rollback this issue?