WHy will my Lg G3 not charge?

My LG G3 was at 15%, I plugged it in for 45 minutes(I made sure it was charging), I came back, Charging logo was still going (IM using a fast charging charger and has charged this phone in the past in minutes) and instead of even going to 16% it went to 12%. Are LG phones that horrible? ive had many more problems with this phone. Is there a way to fix that or should I just throw this phone in the trash and switch 2 apple? Ive never heard or experienced this crap with IPhones.....