Product: Credit card

In XX/XX/2016 Costco forwarded all my credit card information from XXXX to Citibank because Costco would no longer honor its accounts with XXXX. I have never used the Citibank card, opting instead to keep an account XXXX - but those credits I earned before Costco switched to Citibank were not applied to XXXX or Costco, so the only way I could access the reward points before the change over in XXXX was to open a Citibank card ( even though those credits had been applied to my XXXX account before the change over. ). In addition I thought I had paid the Citibank card off, which were charges that had reverted to Citibank, but one payment of more than {$3000.00} was not credited to the Citibank account. When I called, Citibank said that the payment did n't go through because the wrong number was used in the transfer, when I had paid by phone. I have used my XXXX checking account to pay both my XXXX card and now payments to the Citibank account, even though Citibank had ALL the information that XXXX had forwarded to them when Costco changed from XXXX to Citibank.I was able to make one large payment to Citibank but not the {$3000.00} owing which Citibank said did n't go through, even though I have used that same checking account number to pay by telephone for the last 20 years. In addition, Citibank charged me {$110.00} in XXXX to renew my membership with Costco -- without my permission. I have never opened an account with Citibank and therefore have charged nothing to the card because I did not apply for a credit card with Citibank. But Citibank will Not dispute those Costco membership renewal charges, instead telling me they would help me get through to Costco - All other disputes in unauthorized payments were taken care of by my other credit card holders, including XXXX and XXXX. I have Never used the Citibank card, other than to pay account balances. Now, I have paid interest on the Citibank card for the past six months, which was not my error, I also have lost {$200.00} in refund points to Costco even though those that refused had been charged to XXXX before the change over was started in XXXX. I also will lose another {$200.00} refund points from Citibank that I accumulated since my account was transfered to Citibank, again unless I open a credit card account with Citibank. I have been making minimum payments to Citibank to try to pay off the {$3000.00} owing which was not credited to my account because the information somehow did not go through when I had the money to paid it off in full this summer. Citibank had notified me of the change over, but the information was confusing to me, in part because of the legalistic language Citibank used, and because of the numerous telephone calls and offers sent to me to try to get me to open a Citibank credit card, which I have never authorized. I did understand the transfer from XXXX to Citibank, but other than that, it has been very confusing. For example I had sent two payments in the same month this summer to XXXX, but the second payment did not go to XXXX, instead it went to Citibank. Apparently I was not allowed to make two payments in a month to XXXX, resulting in higher interest payments to XXXX on money I thought I had paid to XXXX. Early on in XXXX, Citibank did " forgive '' some interest payments resulting from the change over but not for the last six months resulting in their error, and not for any of the {$400.00} points I have supposedly earned with Costco, or the unauthorized {$110.00} charged to my non-existent Citibank credit care, along with me losing all refund points from Costco. 
Thank you