Mobile phone enquiry

Hi basically I sent my phone off to LG last year to be repaired because the camera wasn't working it came back fixed but i noticed that there was a different battery in it. Ever since then the battery life has been rubbish but now the phone won't turn on, if i charge it the phone turns on and says it charging but turns off again but comes back on then turns off constantly. Is there any hope that it can be fixed? Thanks