Food Panda — coupon code

I opened up a new id in foodpanda, but they are no letting me to use the coupon code. Whenever i try to use them, it displays you don't have any coupons, while my friends are able to order using those same coupons. I tried to send them a email but it has been 6-7 days, still i haven't heard from them, not a single reply from their side. If this persists many customers will be bound to unfollow foodpanda.