Complaint Review: Samsung

I bought Samsung Galaxy M31 2020 on 22/07/2020. At the end of 1.5 months, the phone's touch screen by itself suddenly gave an error, causing the phone not functioning at all. 

I sent the phone to the authorized technical service of Samsung. They accused me of using unauthorised software on my phone, which I never did. I only installed the well-known apps as available by the Google Play Store. They try to charge me 850 TL by claiming that it is a user error so not under warranty. 

I am pissed off because I bought a broken phone that gave an error in 1.5 months and they try to charge me while the phone is still under warranty.