How do I redound my money

Respected Lawyers, Hello. I have buying mobile IPhone 5S (32 GB, Gold) on line in last month from Amazon in website. Within a week receiving the good, because of several reason like very less lifetime charges and battery was damage, screen fluctuation … etc. I have sent to the authorized apple service center for repair. They have denied to give services due unauthorized modification and given the Denial letter with the following reason. Observation- “We checked the device it is out of warranty and it is shown as IPhone 5S 16 GB MM in apple site, it has unauthorized modification so we cannot provide service”. Which is supposed to be genuine and new device. There for I have send the denial report to amazon.in service center, and they are accept those fault and they promises to return the good within 24-48 hour but they postponed day by day and not return my mount. Would you please guide me how do I against them to refund my money? Shall I give compline to the police or not?