Uber India — Promo code didn't work

Address:	Mumbai City, Maharashtra, 421201
Website:	Uber.com

On 3 may 17 i booked a uber from palava city to phadke watch center dombivli and applied promo code for 1st ride at that time it applied successfully but did not get cash discount on finishing trip.
When i tried to get help from uber app it shows that your promo code facility for account is stopped because of t&c so then why promo code applied successfully at first place then.
My uber user id is [protected].
Kindly check the matter and stop fooling the people