If a law firm on behalf of a company sends a cease and desist letter and says you must have no contact with the company or its employees or a restraining order will be brought against you.....can they really do that?

I mean if you are friends with one of the employees it doesn't seem a company can really say "you can't be friends with them anymore". Can the employee get fired for being friends with someone blacklisted?

Any thoughts on this would be great.

If you get a cease and desist letter I'd take it seriously.