i4 won't charge, though the charging symbol still comes on.

I initially began having charging issues a few weeks earlier when my I couldn't let the battery % drop below 30 because when i tried charging it after it crossed that point it never charged it stayed the same % (even though it displayed the charging symbol) and as soon as i disconnected it, it just went off and if i tried to turn it on it kept restarting over and over again. Sometimes if i ditched the adapter and charged it with the laptop instead, it worked. Since the past two weeks even that stopped working and I had to leave the phone alone for at least 24 hours following which it came on without having to press the lock button; like even if I so much as touched the home button or something. Today, nothing will work. The phone won't even restart or anything it has stayed at 6% since hours (again the charging symbol comes on but no actual increase in percentage). I've reset my phone, erased all content, even cleaned out the lint or whatever, but there wasnt much and I keep my cables in a case and even my phone case has dust plugs so i dont believe that was the problem.

I'm confused because i have two different usb cables which work perfectly with my other apple devices. Is it the battery? Defective parts or wires around the battery? If anyone knows what may be wrong please please reply.

Thanks in advance.