If a relative pays for your cell phone, it does not automatically grant them access to your texts and the apps on your phone. However, there are certain scenarios where they might be able to access your information. Here's what you need to know:

1. Direct Access: Generally, your relative would not have direct access to your texts or specific apps on your phone unless they have installed monitoring software or have access to your phone's login credentials [1].

2. Phone Bill: As the person paying for your phone bill, your relative may have access to the billing details, including call and text logs. This means they can see who you have been communicating with and when, but they won't be able to read the content of your messages or access your apps [2].

3. Phone Ownership: If your relative is the legal owner of the phone, they may have more control over the device. In such cases, they might be able to install monitoring apps or use parental control features to access your texts and apps [1].

4. Privacy and Boundaries: It's important to have an open and honest conversation with your relative about boundaries and privacy. If you are uncomfortable with them having access to your personal information, discuss your concerns and consider finding alternative arrangements for your phone plan [1].

Regarding the incident where your relative called one of your friends without knowing them, it's unclear how they were able to do so without more information. It's possible that they had access to your contact list or used a shared contact list associated with your phone plan. If you suspect any unauthorized access or misuse of your phone, it's important to take steps to protect your privacy and consider changing your phone plan or device [2].

Learn more:

1. If a relative pays for my cell phone, does he have ... - Quora
2. ‎Can my parent see my messages? | AT&T Community Forums
3. can my mom read my texts if i share my ap… - Apple Community