Food Panda — unable to apply promo codes

Website: Food panda

Apart from restaurant offers i am unable to use any other voucher / promo codes even though the same promo codes are not for first time users.

I don't know whats wrong. I have followed up many times with the customer care wherein i received the following revert.

"We have identified the unfair use of coupon code in the past with your registered account, due to which your account has been restricted from applying coupon/ voucher codes. This is part of our regular security exercise to prevent unfair means of coupon usage. We deeply regret the inconvenience caused."

On asking the meaning o[censored]nfair use of the coupon code no reply has been received from the customer care even after sending various mails and reminders.