Your rights under the FDCPA
Collectors must send debt details (amount, creditor, your dispute rights) — within five days of first contact if not immediately.
Dispute in writing within 30 days and collection must pause until they verify the debt. Sample letters live at the CFPB site, free.
No threats, no repeated harassing calls, no fake legal claims, no discussing the debt with your boss or neighbors. Violations are reportable to the CFPB and your state AG.
You can require written-only contact or bar workplace calls, in writing.
Playing it well
Wrong-person, wrong-amount and too-old debts are endemic. Paying an invalid debt can even restart legal clocks in some states.
Time-barred debt generally can't be successfully sued on — but a small 'good faith' payment can revive it in some states. Get state-specific facts before ANY payment.
Lump-sum settlements for less are normal. No payment moves until the terms — including deletion or 'paid' reporting — are on paper.
Default judgments enable garnishment. Showing up (or legal aid showing up with you) collapses many weak cases.
Sources: CFPB — Debt collection rights + sample letters · FTC — Fair Debt Collection Practices Act