I got a call from a friend saying they got a call from me trying to sell them something. I didn't call them. How was my telephone number used by them in caller-id?
Unfortunately there is not much that can be done. Usually these callers are spoofing legitimate telephone numbers, so tracing the call is difficult.
Spoofing a telephone number is illegal. So you can contact authorities and they are supposed to deal with the problem. But it is difficult.
Your telephone company must provide you with the ability to block the number. But often the people will just start using another number. Voice Over Internet Protocol (VOIP) technology allows the caller to do spoofing easily.
Here is a link that will help you follow up on the problem. https://www.fcc.gov/consumers/guides/spoofing-and-caller-id