Samaung - Handling of Mobile carelessly and tamepered original parts

I purchased a Samsung mobile Model (M**) on **.**.** (IMEI No. ***************) through Amazon e-commerce website with warranty existing till **.**.****. On **.**.**** my mobile display unit got damaged. I approached the Samsung Authorised service Centre at Vizianagaram for repair. After examining it, I was told that warranty shall not cover any physical damage and generated a service card (no.**********) with an estimated cost of Rs. **** and took * days to replace the same.
Later, they informed me that the camera also needed to be replaced. After my consent for replacement they took almost * days to get it repaired and handed over the mobile, stating that OQC was done as was working perfectly. They also generated a report of the checks exercised during repair of the mobile. I received the mobile after paying Rs.**** towards repair and found out that certain features like Screen rotation, wifi, bluetooth and fingerprinting were not at all functioning. I immediately approached them. After verifying it, the service centre people informed me that the mobile needs complete observation for ** hours to find out the actual defect and generated a new job card No. **********. The next day they informed me that Motherboard was also damaged and stated that it would further cost Rs.*,*** for its replacement..
I argued that either the motherboard should have been defective from the date of purchase or the service centre might have mishandled the mobile during the repair. I also argued, if the defect lies with the motherboard, how was the mobile working till date. I demanded that the warranty should extend to the motherboard. The service centre people have come to terms to refund the amount which I had already paid of Rs.*,*** (receipt enclosed) and further offered a *% percent Samsung Loyalty Customer discount if I purchase a new mobile. However they have not returned my mobile because the damaged parts were not readily traceable and and promised that the mobile will be returned in due course. After continuous pursuance with Samsung Customer care and Service centre Vizianagaram I received my damaged mobile back. To my surprise, my mobile that my entire mobile was tampered with different screen. My damaged screen had damages near camera which is top most corner however the replaced display to my mobile screen which appears to be brand new and without any damage. I had a photo of my earlier damaged screen so that I could identify the misdeed done by the SC VZM. Soon after recognising this I immediately called the personnel at SC VZM named Mr. Prasad, he admitted that my mobile screen was misplaced while sending to samsung Vijayawada central office and they have replaced with it another such damaged screen. Not accepting to this, I told them I will not accept this and I need an explanation for the damages and tampering. I requested Samsung service centre VZM for compensation for deceiving and avoiding to reply all these days. They still informing that the warrenty will not extend to the mother board and I need to pay mother board charges also for getting it repair.

At this juncture, I and my family being loyal customers for the Samsung products, feel disappointed and displeased with the behavior of the Service Centre, Vizianagaram for handling my mobile irresponsibly and making my new mobile (still under warranty period) permanently useless.
I hereby enclose all the relevant documents like invoices paid by me for your verification in order to examine the gamut of issues related to the damage inflicted to my mobile, making it permanently useless.

This issue was even brought to the notice of Samsung Customer Care. However they have not taken any action to any of my incessant mails but always giving dodging replies and following delaying tactics. This caused me lots of inconvenience and caused lots of financial hardship during COVID pandemic. Our children suffered with enormous loss by missing online classes for which the most purpose of buying mobile was defeated.