Sony Service Centre tricked me, replaced my phone with old one.

My XA had a very tiny dead/stuck pixel on the right side of the nav keys which was only visible on white background. There were few days left to my warranty, so i visited local service centre on 17th of January, where they told me that they will check the device and see if they could replace the screen. They gave me receipt but it didn't mentioned the "JOB SHEET NUMBER" (as it was my first time to submit a phone in sony service centre, so i wasn't familiar about it) and they told me that it would take a week. After the week passed, i directly called the Customer Care to check the status of my device and they asked for the JOB SHEET NUMBER which was not given to me, so the Customer Care told me to contact local service centre to get the number. So i called the service centre and asked for JOB SHEET NUMBER, but they said that "THE JOB SHEET NUMBER IS NOT BEING GENERATED FOR EVERYONE" which after researching, it was a lame excuse. So i got the call from service centre on jan 29 that my phone is ready to pick. When i enquired what was the problem? They said, "THE MOTHERBOARD, CHARGING PORT AND DISPLAY HAS BEEN REPLACED" (ok i understand why display was replaced, but why the heck was motherboard and charging port replaced?).

When i picked the device i was shocked. The condition of the device was so bad that i had a feeling that this can't be my device. The metallic sides were scratched so bad (very deep scratches) and the entire back panel had deep scratches and it had marks of fingers like the device was being used without back cover or any protection for very long. The same case was with camera lens, it was badly scratched as well.
When enquired about the bad condition, we had an argument, after which he changed the metallic sides and said that they don't have back panel and camera lens available rightnow and agreed to get it it fixed.
When i reached home i tried to insert the sim card and when i pulled the sim tray (simcard holder), it was cracked. The thing that shocked me was that this wasn't the simtray my phone had, because my simtray had a little mark on it, which it didn't have.

On Feb 2nd, The guy at service centre informed me to get backcover replaced as it arrived today and after reaching there, i told him to pull off the back cover in front of me (i had already watched a video "how to dessemble xa" on YouTube). So when he pulled the back cover off, i saw there was no "COPPER LAYER ON BOARD" which is supposed to reduce heat from chips and i was shocked to see the "DENTS" on the motherboard, the question is IF THEY REPLACED THE MOTHERBOARD WITH NEW ONE WHY DOES IT HAS REPAIR TRACES?. So it's clear that the service centre guy just replaced my new phone with old one and and after emails, calls and visiting service centre again and again (even though it's around 40 KMs away from my home), neither sony nor service centre is helping me.

FROM 2 TO 3 DAYS MY DEVICE STUTTERS (LAGS) WHILE SCROLLING WEBPAGES AND VIEWING PICTURES IN ALBUM, which I'm definitely sure that it didn't happen before.

The service centre is at ABI GUZAR, SRINAGAR, JAMMU AND KASHMIR named as OHI ENTERPRISES.

I want my device to be replaced or money to be refunded.