Several problems with my Galaxy S4 :(

[Arrhenius]

Hi, I've recently gotten an S4 over the internet and I've been having a lot of problem with ironing out some problems with it lately.

1.) Whenever I unplug the phone, lock it, and go to sleep, even if its on 80%, the next morning it will have completely run out of charge, I've asked my friend, who also runs an S4, and he doesn't have similar problems (he also runs the same apps I do, Skype, Whatsapp, etc)

2.) Whenever I call on skype via the S4, the screen keeps flashing (goes pitch black, then fine, pitch black etc), sometimes for a second, sometimes longer (when it doesn't turn itself back on again, pressing the main button will trigger it, but the peripheral menu/back button doesn't respond). Also touching the top of the screen will trigger it to go black during Skype calls, and the blue LED light flashes like crazy during this period.

Now I've tried uninstalling skype and reinstalling it, but the problem persists, and I've not found any solutions to this over other forums and I would like to ask if there are any fixes to this? Or is it a bug on Skype's side.

 

[Bosbouer]

" 2.) Whenever I call on skype via the S4, the screen keeps flashing (goes pitch black, then fine, pitch black etc), sometimes for a second, sometimes longer (when it doesn't turn itself back on again, pressing the main button will trigger it, but the peripheral menu/back button doesn't respond). Also touching the top of the screen will trigger it to go black during Skype calls, and the blue LED light flashes like crazy during this period.
"

This is most likely related to the proximity at the top of the phone that senses something close and shuts off the screen.(It is setup to blacken the screen during phone calls where you have the phone next to your ear).