PhonePe — cash back not yet received

Website:

www.phonepe.com

Dear sir,
I ordered some goods trough flipkart on 08sep2017. At that time there was an offer prevailing that if we paid through phonepe we will get 50% cashback up to a maximum of rs.100/-, so in order to avail this benefit i made the payment through phonepe. The cashback must have been received within 24 hours but it has been more than 15 days since then, but i have not received my cashback till now. When i contacted supportcare system of phonepe they provided me with some useless and unneceessary resoning as to why i have not received my cashback yet... Kindly look into this matter and resolve my grievance at the earliest.