You need the 16 digit of your card number & security code of your card...
Check your master card gift card balance online, please enter your card 16 digit numbers followed by 3 digit CVV code of your card located on the back of your card.
To reach a customer care call at 1-800-571-1376.
URL: www.vanilagiftscards.com/mastercard-gift-card-balance.php