The debt collector may contact anyone to obtain "location information." They cannot tell that caller that they are collecting a debt, only that they need to speak with the debtor about an "important matter", a "business matter" or similar.
They can dun the cardholder and the joint cardholder, but not someone who is only an "authorized user" and not liable on the account. They can dun the spouse (the law is not clear whether this is only the current spouse). They can communicate with anyone authorized by the debtor, such as his/her attorney. They cannot dun a parent of an adult debtor. They cannot dun a neighbor, a babysitter or other relatives. This applies only to "consumer debts", not business debts.
Each violation, if proven, can give rise to between $100 and $1,000 in "statutory damages" under the FDCPA. Also, they cannot call at work if they are told that you are not allowed to receive debt collection calls at work. And, they cannot call after you send them a letter asking them not to call.
If the debt collection agency does not comply withe local rules and contacts someone outside that list in violation of the rules then they may be liable.
Legal disclaimer: The response given is not intended to create, nor does it create an ongoing duty to respond to questions. The response does not form an attorney-client relationship, nor is it intended to be anything other than the educated opinion of the author. It should not be relied upon as legal advice. The response given is based upon the limited facts provided by the person asking the question. To the extent additional or different facts exist, the response might possibly change. Attorney is licensed to practice law only in the State of Massachusetts. Responses are based solely on Massachusetts law unless stated otherwise.