E-gift certificate trouble

[Fuzzy Necromancer]

Early christmas morning I sent an e-gift certificate to an email address, and was told the address wasn't a valid one. I sent an email to the same-address and the email went through, and I got a confirmation of purchase for the gift certificate. Will I still be charged for the price of the gift certificate? Is there any sort of eccentricity that would make a type of email  handle poorly? (Such as a period between two words but before the @ symbol, or  a certain type of email account?)