I deleted a bunch of contacts because I imported the wrong data pertaining to them. I then imported it again, with the right data and it wouldn't let me because of "duplicate" contacts. However I searched for these duplicates and they do not exist. I am at a lost with what to do. Changing their ID isn't an option here. ALSO do note that when I do an advanced search, I do not have the option to search in trash.
Maybe, they are still inside the recycle bin? CiviCRM doesn't delete them form the database, it just marks them as deleted.
Do "Advanced Search" and check the checkbox for "Search in Trash (deleted contacts)"... and delete them a second time! :-)
I had a look into my system! I'm using Drupal, and there is a right (permission in Drupal) called "Access contacts in the trash"!