Not a whole lot can be done with a first and last name and a phone number. If someone is motivated they don’t need any of this to do harm.

As an example at my job people know my first and last name and I give it to people voluntarily without knowing anything about the other person. While I don’t give out my personal phone number, I know lots of people that do. Sometimes on their business card or even email.

You may be over thinking this and just use it as a lesson to be a bit more guarded and aware of social pressure in the future.