The return envelope should be free ... tear up the stuff they sent and mail it back with a note to remove you.
TFM:
Found this for you ... ya gotta love Google:
Notifying all bureaus with one phone call
1-888-5-OPTOUT is an automated service run jointly by the four main credit bureaus. With one phone call you can opt out of pre-screened mailings from all four bureaus.
1. Call 1-888-5-OPTOUT.
2. Select option 2 to skip a message about an internet email (described below).
3. Select option 2 to opt out of mailings permanently. Be careful, because option 1 only opts you out for two years.
4. Follow the prompts to enter your phone number, name, zip code, address, and social security number.
The service states that your request will be processed within 5 business days, and a "Notice of Election" form will be mailed to you.
The only true way to get them to remove you is to use their prepaid reply envelopes to send back your rejection and your request to remove you (I just write mine in ink). If they keep coming, start filling up their envelopes with garbage. They have to pay all the postage and if they get nothing, eventually they'll stop. I read about one guy who started putting metal scraps in his. If it comes to that, too bad, but at least you'll be off their lists. Do that for every junk mail offer and eventually you'll be junk mail free.
Commenting by HaloScan
