Creditor Collection Letter Response

[coopercty]

What is the name of your state? PA

My father passed away in November of 2005. He left no estate and he had several outstanding credit card accounts which were in his name only. Upon his death, my mother, who is 78 yrs. old, provided each of the credit card companies a letter stating that my father was now deceased,that there was no estate, provided them a copy of the death certificate, and requested the accounts now be considered closed. She does not own a home or automobile. Subsequent to sending the letters, she has now continued to receive letters from the creditors asking for payment as well as harassing phone calls from one of the credit card companies requesting her lawyer (what lawyer?) handling the estate (there is none) call their laywer to discuss the issue. She owns no property, the accounts were all in my father's name, not joint accounts, and she lives on a fixed income. None of the accounts have been turned over to any collection agency as of yet. What other options or actions can be suggested in this case to ensure that these accounts, which she is not responsible for, are closed out. Thanks for the help.