Discover Debt Collection Complaint

Discover Debt collection department,

Credit card Cont'd attempts collect debt not owed Debt is not mine Georgia

This is dealing with an Estate Debt. A major credit card company hired a Collections Agency to collect a CC debt after my mother death. I am the legal administrator for the estate. Upon contacting both the CC and the debt collector, I was told by the CC the debt collector is the only - that can now neg. the debt with me. Upon contacting the debt collector I was informed by the collections company that if I wanted to settle below a certain amount, they would need to verify the amount in the estate account and where asking me to provide a bank account statement. I feel they have no right to request such a document. Is this legal?