Blackberry mobile z10

Dear concern
on 29 june 2014,i had purchased blackberry
mobile handset z10 from ebay in dia.
.From day 1 i am facing restart problem,battery drainage &
shut down on 50% battery.I had wrote so many time to brand
helpline,but all in vain
.pls help

Thanks
Sandeep kr
HNO 2 GALO NO 2 EXTN KUN DAN NGR
Ferozepur
96533-18600