I'm sorry you are unable to remove contacts as easily as you should. At which step are you having trouble with trying to delete contacts? What page of your account are your trying to delete them from? Are you trying to remove bounced contacts from your email reporting? If you are trying to remove contacts from the bounce reporting you can do this by selecting all contacts, clicking the Actions button, then choosing delete in the drop down.
You will then be given a notification saying that these contacts will be removed from your account with the option to be readded in the future. To prevent these contacts from being added back in the future, we suggest exporting this list of contacts and upload it directly to your unsubscribed list. If this isn't what you were looking to accomplish,