If you have deleted them from your Amazon Account, then all you should need to do is sync your device to your account (after the deletion from the account) and it should also delete them from your Kindle.
So, the first thing to do is to delete them from your Amazon account.
How to remove items from your Content Library.
This is for permanent removal of books, audiobooks, periodicals and/or personal documents that you have in your content library.
NOTE: If you deleted something from your "Mangage Your Content and Devices" you will no longer have access to it and will not be able to re-download that item, without purchasing it again.
To remove items....
1. Go to "Manage Content and Devices".
2. From your Content change the Show drop-down menu to the category of the item you wish to remove.
3. Choose the title(s)/name(s) of the items that you want to delete.
4. Once you have selected all the items you wish to remove, select "Delete".
5. To confirm that you want to delete it/them select "Yes" and this will delete the item permanently.