will PC Specialist resolve this issue or should i send my laptop back?
It sounds like Windows DPI scaling functioning as intended to me. If an app wasn't running in FHD that's probably down to the app not being compatible with scaling yet, a lot aren't - or because it wasn't meant to. The purpose of display scaling is to make things more readable on a smaller screen, such as web browsing. Scaling in general isn't very good on Windows at the moment (blurry text on some applications etc.) but that's very much a software issue and nothing to do with the hardware. 1920x1080 is usable on a 13.3" screen so if you should be able to turn DPI scaling off if you wish and run at the native resolution.