You contact the subscription number inside the magazine and let them know. You know those self-addressed, pre-paid postage subscription cards that are always in magazines that end up falling out onto the floor when you flip through it where all you have to do is fill it out and drop it in a mailbox, not even needing a stamp? Well, there's a pretty common prank people pull on other people, either trying to be funny or trying to be mean, where they fill those cards out with the name and address of someone they know. When they're at the salon, they'll fill out five of them. When they're at the doctor's office, they'll fill out five or six more. When their own magazines come in the mail, they'll fill the ones in those out, too. Pretty much whenever they find one of those cards, they fill it out with that person's name and address. Soon, that person is getting buried in magazines and in unpaid bills from magazine companies. There's nothing you can do but call the subscription number in each magazine and tell them that it wasn't you who subscribed. That'll usually work to get the bills canceled so that they don't go to collection, but for whatever reason, it seldom works to stop the magazines from coming, like magazine companies' billing departments don't talk to their distribution departments, so don't be surprised when all those magazines keep coming.