What to do, my phone wont charge or turn on?

Hey everybody! I've had this phone( LG L70 D320 ) since christmas 2014 and it's never been a problem. However now I'm faced with (I'd say) a rather big one! About.. maybe 3-4 days ago, my phone kind of.. died.. I remember it was low on battery in the morning, so I plugged it in as I woke up and it started charging. I went to check on it later, whether it was done charging already or not. Usually it takes almost no time to fully charge. But instead, it had just turned off.

As the cable of the charger is somewhat broken and works only if held in a certain way (we have our own trick for that), I just figured that I had forgotten to "work the magic" on it to make it work. Later my boyfriend tried as well, but it didn't work neither (worked fine on his phone). He said it's the chargers fault probably. (the cable of the charger that is..) So today i purchased a new one and replaced it with the old one and still got nothing, except for that it made a connecting sound on my laptop when I tried connecting it to the laptop.

Ideas?