Broken phone sold

I purchased a used iPhone 8 from isupplyza operating on Instagram on 27 June 2022 for R4499.00 The owner of the business left the phone with her sister for me to collect. The phone worked perfectly fine. However, in August month the phone's back camera started to act up, and the screen would excessively shake up and down while attempting to take a pic/video that you can even hear the camera performing this action. I DM'd isupplyza on 24 August 2022 notifying them of this issue, they rep**** saying my phone must've fallen. I advised it has not. Since then my front selfie camera has been doing the same thing and also makes a noise, and my speaker also doesn't work anymore. Now, this is the third PRE LOVED iPhone I purchased. The 2 previous phones gave me no issues whatsoever, the one I passed down to my daughter and the other was ******. Both of which those phones had fallen but never ended up with this type of camera and sound issues. In my experience, I believe this was a broken phone sold to me and there was no empathy to even assist me.