I think the phone is so old and cheap parts might not even be available.
Your best bet is just to get a new phone. There are brand new phones you can have for around 100-200 dollars that work amazing and do everything a smartphone should.
The Samsung Galaxy Prime is just one example. [https://www.amazon.com/Samsung-Galaxy-Grand-Prime-Smartphone/dp/B00TJ1WB1W]
There is plenty of others like that, just do some searching to find one that fits your needs. You could also look at a used, newer iphone or samsung for around the 300-400 dollar range