Intex Power Bank — not working

Address:

Jabalpur, Madhya Pradesh

Hello sir,
I bought a intex it-pb12.5k 12500mah lithium ion power bank (Black-grey) through amazon on 24th jan 2018. But it was not working to get charging... It is taking charging but when it attached to mobile it is not charging.. So please do needful... I m very dissatisfied by this company service which is not providing costumer service. Please resolve this problem as early as possible...