Uber India — banning my account from using promo codes

Website:

Uber.com

Hi,
I am getting good uber promo codes through sms on my mobile. But whenever i try to use them out shows invalid code. When i contacted uber customer care they said my account was flagged due to some issue and i will never be able to use any promotional codes ever. I am pretty sure i haven't done anything that could have led to this. I have been a loyal customer o[censored]ber and have been using their services for last 2-3 years regularly. This is just cheap tactics they are using to attract customers and then not allowing them to use promo codes. I am not getting any satisfactory reply from their customer care. Also if they really banned my account then why are they sending personalized promo codes to me?
Please help.
Thanks,
Rahul