Not giving paid amount

I have Nokia 8 Sirocco mobile & screen got damaged. I have sent for repair through Nokia Support & they taken. After i came to know that, Nokia have their 3rd party named SERVIFY and this SERVIFY only looking these issues. Later i received a request of money which is 22853/- when i enquired about this, they told device is not repairable & they can replace it with new device. So i paid the amount but as per committed date, they didn't sent my mobile. Then i asked them for refund my money & old device. They delayed the process for 10days ( through call i clearly told them, I didn't require their service as it get delayed. Whenever I call them, they always say we're checking your request with back end team) i have done plenty number of calls & mails written to them. At last they're saying that, we arr helpless in this regard & forcing me to take the device.i want to file a case on them. Please help me how can i proceed. Is my reason is valid or not. Can contact me [deleted] & mail: [deleted] Thanking you