SPAM is unwanted, unrequested email similar to junk mail you get in your regular mail. Frontier Internet does not sell its mailing list to anyone - nor do we give out email addresses.
Spammers get email addresses in a number of ways.
The most common is if you sign up for, order from, or enter a contest on the Internet. Obviously impossible to do. There are many other ISPs, however, who are not so ethical and some make a lot of money by allowing junk mailers to use their systems to email garbage out. Unethical but way too common, I'm afraid. If someone emails us looking for you, we forward the email to you and leave it up to you to contact that person.