Citibank Credit Card Complaint

Citibank Credit card department,

Credit line increase/decrease Missouri

I allowed my son to use my account and he paid the bill. Upon his passing we found out that the balance was over $17000.00. and we were told that because the account was in our name we were responsible. Our credit limit was -, very sufficient, but Home Depot took it upon themselves to extend credit beyond that amount. I feel that we should be resposible for only charges upto the credit limit. I have never heard of any credit card extending credit without the knowledge, consent or request of the card holder, but I guess with approx. 24 % int. they did n't care.