My wife owed about $30,000 on three chase credit cards. They were resultant from my use as an authorized user and she didn't know about it. As an authorized user I am not responsible by law. We separated and she told the company that the charges were not authorized by her. They reversed about $20,000 of the charges and sent her February and March bills reflecting the lower balances due. Now, she has gotten new bills and a letter stating that they were adding the charges back to the accounts, so the balances are about $30,000 again. They said she benefited from the charges but she didn't. Since they sent her the 2 bills with the lower amount... can they add back the charges? Thanks for any help.
No, there were no fraud charges filed and chase said they couldn't fiind any evidence of fraud.

Yes they may add them, if they were not authorized by her, they are fraud, but they were authorized by her since you made them and she authorized you to use the card.

She may sue you for the money if you refuse to pay her.