Blackberry — Mobile Shop "City Mobile"

Dear Sir, I bought a mobile Black Berry Z10 from City Mobile, Madgao, Goa in 2014. Since I purchased this mobile I told the shop owner to change this mobile as having network and battery problem in this mobile but the owner did not replace. After that I went to resolve the same problem to BlackBerry authorized service centre(Panjim) there I came to know, this mobile is from abroad one so you can not get service here and if you want then you need to pay our service charge. After complaining the same to owner he told I will give service and that time he updated my mobile. Now, from last more than one month, neither he gives service nor receives my number. Kindly pay your attention to resolve this issue or guide me. Regards, Ashok