Collection agencies and other such companies that wish to collect on a consumer debt must abide by the federal Fair Debt Collection Practices Act. This prevents them from abusing people as they attempt to force payment, engaging in oppressive and unfair tactics, harassing debtors or using such techniques against people the debtors may know.
In some circumstances, a collection agency is allowed to contact the relatives and acquaintances of a debt holder. They may make contact with a third party to attempt to find the address of the debtor, their phone number or their place of employment. Under most circumstances they are only allowed to make contact with them once.
Under the FDCPA, the collector has a responsibility to provide the debtor with a copy of a validation notice in writing. The validation notice must be provided within five days of their first contact with the debtor, and it must clearly identify the creditor. The debt may be disputed if the putative debtor does not believe that it is rightfully owed. All that is required to dispute a debt is to mail a letter to the collector that explains why the debt is invalid or another reason why the alleged debtor should not be held liable for it. The notice of the dispute must be sent within 30 days of the receipt of the validation notice.
The collection agency will be legally prevented from contacting the creditor again until it produces and sends written verification that the debt is real. If the debtor chooses to retain the services of a lawyer, then should may inform any collection agency or other party attempting to collect on a debt that it now has to contact the lawyer directly in order to prevent any further harassment.
Source: Federal Trade Commission, "Debt Collection", December 29, 2014