My mom got a new phone (Samsung Galaxy A13 5G) and it's having problems with phone service. I'm not much of a phone person, so I was hoping someone here would be able to help us.

Her phone is having two issues:

1. Texts from other phones are received several hours after they were sent when she's away from home, texts that she sends always go through instantly. If she's at home, she always gets texts instantly.

2. Her phone keeps coming up as "offline" on some other phones.

As I stated in the title, I'm not familiar with phones, so I have no idea where to even start with this. I have done nothing more than a google search that didn't give me any results relevant to the issues.