Replaced battery, phone overheats and won't charge past 50%

Hey i replaced an old battery for a friend yesterday, He told me today the phone gets pretty hot and won't pass 51% when plugged in, When putting the battery in I may of done it crooked and I was having a bit of trouble getting the connector in, i had to bend the cable a small amount and i finally got the two prongs in and put a screen on to make sure it powered. All worked so i put her screen back on, the connector didn't sit flat which was strange but it worked so i figured it would be all good. I'm thinking the issue may be because of what i am talking about above, i'm gonna take her phone apart again and redo the battery connection and use a new battery incase I damaged it. But yea I think the connector may not be seated correctly, do you think that is my issue ?