Many iPhone users face chargin issues, mostly issue is not hard to fix and we have given few tips that works for many users, My advice is you should give them a try one by one. Last option is always go for repair or new handset Try reseting the iPhone
1. Switch the mute switch 4 times (up, down, up down)
2. Now press home and power for 6-10 seconds Try Changing or removing sim card Check Charger and charging wire workin fine Try the battery Change, with differnt or new battery.
Good luck and keep us posted with your results