Product: Credit card

I have been a Discover Card consumer since XXXX of XXXX ; thats XXXX  years! Throughout all those years, I have paid my account in full and on time. On XX/XX/XXXX, I received an alert of a {$460.00} charge to my account. I was shocked to receive this because I had previously locked down the account. I locked the account to prevent an authorized user from using it because that person was being influenced by a bad individual. I immediately called Discover to find out how this could happen and was told that the account had been unlocked and the charge could not be disputed until it moved from pending to posted status. I was told to close the account to prevent any further activity, open another account without the authorized user, and to call back to dispute charge once it is posted. I did not want to close the account that I had for so long and even had the account number memorized, but I did it with the assurance that there would be no further activity from XXXX and that I could open a dispute once the {$460.00} posted to my account. Because I had closed my account, I was unable to view the status of that charge so I had to call to ask if it had move to a posted status. When I called on XX/XX/XXXX, I was told the charge was no longer on my account. I thought that was the end of it, but on XX/XX/XXXX a got notice of a XXXX declined toll charge and then found that on XX/XX/XXXX a charge of {$700.00} was posted to my new account without my knowledge! I called Discover AGAIN and filed a dispute under Case # XXXX. Subsequently, I received notice that it was PERMANENTLY removed from my account on XX/XX/XXXX. I also received a noticed that XXXX was blocked from my account. Then on XX/XX/XXXX a notice was generated and mailed saying not that the case was not settled in my favor and the {$700.00} charge was posted to my account again. I called once again on XX/XX/XXXX and opened yet another dispute and then later spoke to a supervisor about the entire situation. The supervisor told me to wait and see what happens with the new dispute. On XX/XX/XXXX another notice was generated and mailed saying that the charge was reposted to my account. On XX/XX/XXXX I called again and this time was instructed to speak to a manager of the Billing Department. After not having success with the manager, I then contacted XXXX XXXX XXXX and was put in touch with XXXX, a consumer advocate, on XX/XX/XXXX who ultimately told me that the authorized user had unlocked my card through the automated system and that is the reason the charge was permitted to go through. He acknowledged that unlocking the card through that pathway did not require a password as it does when doing it online. I was also told that if I had closed the account and not established a new account, the reposting of the charge would not have gone through. 
My dispute is with Discover allowing a charge to go through on an account that I am the owner of and responsible for. Discover should have the same password controls in place to unlock an account through an automated system as it does when unlocking a card online. My authorized user did not have my password or authorization to unlock the account. In addition, I was advised by Discover to open a new account without the authorized user rather than just close the account entirely. The XXXX charge is now on an account that no longer has the contracted renter listed which I question the legality of that. This is not fair business practice and Discover should be held accountable for the companys deficiencies.