Infibeam.com — Replaced Original battery with a used battery in my Xperia

Yesterday I received the Sony Xperia M mobile I bought from infibeam.com. The outside infibeam packet was intact, but the inner sony pack looked like already opened and sticked back. Once I opened the packet, the battery was lying outside its cover and on further checks, i realized the battery kept along with the mobile was a 1700mAh battery, which looks already used by someone. The mobile clearly mentions that the one that comes with it is a 1750mAh 13W32 battery, but the battery i received along with was a 1700mAh 13W28 battery. This looks like a deliberate attempt to cheat the customer. I contacted the customer care, and initially they asked for the photos of the product. I sent them the photos straight away. Now they are saying they have forwarded that email to someone else. I feel this is some delaying tactics to confuse the customer and ship another old product till the customer gets fed up with complaining.