A pre-authorization on a credit card removed those funds from available credit, but will not count as a charge until the actual charge is initiated. However a debit card works slightly differently. With a debit card the funds become unavailable prior to being actually removed from the account, but as this is tied to a bank account those funds cease to be available for any use at all until released by the issuing bank. 

Example: if your bank account has a €2000 balance and an €8 pre-authorization has been

made only $1992 will be available for access for other spending purposes. If the €8 account charge is successful the €8 will be permanently removed from the funds, if the account is cancelled prior to the charge during a trial period, once the pre-authorization has been released the €8 will once again be available.