Order returned but Gift Card Refund not received.

My order no  was placed on 1/29 and due to some product issues the order was immediately returned to Dell office. Got confirmation on 2/12 that item was received and refund was initiated.  My credit card account got refunded immediately without any issues. However I did use 100 and 50 dollars dell gift cards during this purchase. I got my 50 dollars gift card back but not 100 dollars. I'm so worried that my $100 dollar dell gift card would expire tomorrow i.e 3/12/2014. I sent couple of emails to customer care but waiting for their response. Could someone from Dell please answer my question as the gift card would expire Tomorrow. Please help me in this.