No. In order for one (1) contactless transaction to be completed, the amount of this transaction must first be entered in the POS terminal by the merchant’s employee. You hold your card close to the POS terminal and, after the transaction is successfully completed, a relevant information message will be displayed on the terminal's screen. 

Once the transaction has been successfully completed, even if you mistakenly hold again your card close to the POS terminal, you will not be charged.