Product: Credit card

My parents have had a Chase XXXX XXXX card with Chase Bank since XXXX. In XXXX, I was supposed to have been added as an Authorized User on the account - NOT a joint cardholder. I have pulled my credit report since then and noticed that their account records are appearing on my credit report as if the card is my own. 
I called to speak with a Chase representative, XXXX, and he advised me that I was a joint cardholder, and not an authorized user. The detailed history is : in XXXX, I was supposed to be added as an authorized user. Instead, what occurred in Chase 's error is that my mother - who was SUPPOSED to be a joint cardholder - was added as an Authorized User and, erroneously, I, their daughter, was added as the joint cardholder. We were unaware of the error then as we were never provided any documentation to review or sign, and I never received any cards with my name on them ( as Chase never had my actual address or authorization ). In XXXX, my mom was sent a letter from Chase bank, advising that Chase will now ONLY be adding Authorized Users, and no longer be adding Joint Cardholders, and that if she wanted to make any changes to the Authorized Users or Joint Cardholders, that she should do it now during their open " window '' for these changes. It was in that documentation that she realized that she had been added as the Authorized User and that I had been named the Joint Cardholder. She called to correct this, and spoke with a representative there, and asked that they correct their previous mistake, as SHE is supposed to be the Joint Cardholder, and should remain so past the XXXX " window of changes '', and that I was her DAUGHTER and was only supposed to be an Authorized User. They advised my mom that they would correct the mistake and send new cards. As it turns out, I was never removed as they advised they would do, and now, since it has passed the Chase " window '' for making those types of changes, we are being told that I can not be removed and I am forever on this card as a joint cardholder, and that I assume the debt - WITHOUT authorization. Again, I have never received a card, a statement, the company does not have my address, never has had my address, and has never received signed authorization from me to be responsible for this card/debt. 
Since, I have never signed anything or completed any paperwork, nor has Chase Bank EVER pulled a credit inquiry into my credit history in order to determine credit worthiness to be added, I have requested, again, that I be removed from this card as a Joint Cardholder completely. 
Since they are insisting I signed something ( which I am certain that I did not ), I have asked to be provided a copy of the document that I supposedly completed and signed authorizing me to assume this debt and be added as a joint cardholder, which I have yet to receive from them. I spoke with a " XXXX '' at Chase, who admitted that there must have been an error ( after reading the account notes ), but is still saying there is " nothing he can do ''. I intend to pursue this matter legally until my name is correctly removed from this card account. It is not now, nor has it ever been, my account. My parents have done business with Chase for a very long time and they do not want to cancel their account and go elsewhere, and closing the account completely is the only option that Chase advised me of, and even doing so does not remove me from being responsible for the debt on that card that I should not even be associated with. I find it insane that - by this reasoning - I could theoretically have a stranger 's name and social security number, make a phone call and just have them added to my card account, and - poof! - make him responsible for all of my debt. This makes no sense at all, legally. Please help.