The specific federal laws that govern billing disputes, debt collection, warranties, and credit reporting — and what each one actually guarantees.
The FCRA gives you the right to see what's in your credit file, dispute inaccurate items, and have the credit bureau investigate within 30 days (45 days if you submit new information mid-investigation). If the bureau can't verify an item, it must be removed. This is the law behind your free weekly report at annualcreditreport.com.
Third-party debt collectors (not the original creditor collecting its own debt) can't call before 8am or after 9pm your local time, can't call you at work after you tell them to stop, can't threaten actions they don't intend to take, and must send written validation of the debt within 5 days of first contact if you ask. Violations can be reported to the CFPB and may entitle you to statutory damages.
Covers credit card billing errors and unauthorized charges. You must dispute in writing within 60 days of the statement date; the issuer must acknowledge within 30 days and resolve within two billing cycles (max 90 days). This is the legal basis for a chargeback dispute.
If a company offers a written warranty on a consumer product over $15 (technically $25 in the statute's original text, still the operative threshold), it must state clearly whether it's "full" or "limited" and can't require you to use only branded parts to keep the warranty valid unless the part was provided free.