Hi i recently bought brand new xperia xz premium on eBay (guy who was selling it stated it as a BNIB ). After opening, the everything looked fine there were stickers at front and back, as well as on the box. I installed all updates and so on and tried to listen some music on YouTube. And than I noticed that the sound is low. I set it up on max volume and it still was low. The same with ringtones. Now I'm confused what might be the problem and is it possible to fix it.
