How to fix iPhone 5C time?

This started happening a few days ago. I noticed the time changed. It was later than usual so I changed it to the right time manually. Then after an hour I checked my phone and it was late again. I kept changing it and the time zone. It kept doing it so I restored my phone and it still doesn't show the right now. Sometimes, it would be correct but after a few minutes I'll be late again. The date doesn't get affected. But I also noticed I wouldn't get some text messages. And notifications are late as well because of the time. I'm getting really annoyed. I told my mom about it and that I might need a new phone but my 2 year contract hasn't ended yet and we don't have money to buy a new one. Is there a way to fix this? I searched it up but I haven't found a single solution that worked.