Why do you want to send a letter to the creditor? If there's something over seven years old on your credit report, dispute it with the CRA as being obsolete.
You don't want to cite 15 U.S.C. 1681 et al. either. Recognize who you're speaking to. This isn't a bench memo or an appellate brief. Just say it's obsolete.
The seven year reporting law applies to the credit reporting agencies. As Hedwig suggested, you need to dispute with the CRAs reporting an obsolete tradeline.
