Ensure you have entered the correct serial number. Serial numbers of all Asiasoft prepaid cards start with two alphabets, followed by 13 numbers. (If you are wondering whether a character in the serial number is a 'D' or '0', it is a '0')
Ensure you have entered the security code as shown on the card. All security codes are in capital letters.
You may send us a message via iBox if you encounter any other problems in charging prepaid cards.