Nokia India - Getting huge issues before and after service

It was started from near about two months ago, my new Nokia *.* (bought on **/**/****) device got a blue spot on its front display panel, also there are many problems seen from that time i.e. fingerprint sensor, the device becomes slow etc. The display panel was replaced by the Nokia Care, but they don't do anything about the fingerprint sensor. After *-* days of getting the phone from the Nokia care, there are new problem seen i.e. vibration not working, fingerprint sensor as it is as previous complained, mobile got excessive heat and the back panel of the device opened automatically. From the first time to till date I wrote to Nokia Mobile Care <support@hmdglobal.com> for look up the matter and also for replacement of the device every time they said that "wait for some time", they don't give any suitable reply about my concern. Their service is not so fast. About the parts availability at their store is null so that my device is lying at their centre for a long time. It seems that I bought a device not for self-use, for using it Nokia's technician's as a device demonstration program. How many times they opened my factory manufactured device to make it a Nokia Care Manufactured device. I want the replacement of my device Nokia *.*.