cellular and primary “phone numbers”

I was out of service for a few days and my friend told me that a way to get better service is to go to general, scroll all the way down to “transfer or reset iphone” and click it, then go to reset and reset my network settings. About 30 minutes later I was trying to text someone and it gave me an alert and i can’t remember what it was but it took me to messages and it said “iMessage uses wireless data to send messages between Apple Watch, iPhone, iPad, and Mac. About iMessage and FaceTime & Privacy” so i clicked on it and it just took me to the messages and facetime page. After that all my friends can’t facetime me and my texts were green, but after a few days my text now won’t send at all.