RAZR v3 wont charge

Hi, I just bought a new battery for my mom’s old RAZR V3 to solve the problem of the phone displaying a message saying “unable to charge”. it will turn on and work perfectly, but the moment I unplug it, it dies. It does not display a battery charging icon either. It originally had a BR56 battery in it and had this problem, so I assumed that a new battery would fix it. So I replaced it with a BR50 and it is still behaving the same. I am going to try finding an original charger, but my mother most likely threw it out. Thank y’all for any help.