Can you add a little more info? When you say "redeemed points for two gift cards".... how did this happen? Was it on line? Did you call and have a Marriott rep assist?
If it was online, did you receive a confirming email?
Your marriott.com account should show how and when the points were deducted. Is it possible that the entire purchase was put on one Giftcard?
In the end, it's always best to call the Customer Service line and explain your situation. They have a Giftcard department that can track your purchase and usage. I'm sure they can straighten this out to your satisfaction....good luck.
These gift cards have registration numbers on them. When they are sent the numbers are recorded. You can call the number on the gift card 800-442-6132. Ask them about your account and the missing gift card. Both should have been sent at the same time. If they do not have the answer, they will certainly be able to direct you to the place where, if the card was sent and not received, they can cancel the gift card and re-issue another.
I always register my gift cards on gifts.marriott.com because then I have an online record I can refer to if I have a problem while on the road.