Ask Me Bazaar.com — Xiaomi Power Bank not working and is used and old.

I orderd a xiaomi power bank of 10400 mAh from the Askmebazzar.com. When I opened the parcel I found that the product was not new and fresh. The plastic box was broken and was having scratches. when I opened the power bank I found that the power bank was not new. When I used it for charging it did not charged my phone fully even a single time. It get discharged earlier than my phone. I charged it fully but then also it did not charged my phone even a single time. I registered a complaint on call to ask me bazzar on call with Complaint id - qrc43655499. Please do the needful for me as soon as possible.