Due to website problems, XXXX identical payments were submitted to CitiCard on the same day. When I discovered the error- a Citi customer service rep offered to keep the overpayment & assign future credit, then - as I protested - agreed to 'try to get a refund authorized ' which would take a few days. 
Considering how vigilante CitiBank is for 'fraud ' and late payment - it seems absurd that a {$9800.00} same day double payment could not trigger an alert to me before it was " too late. " In addition, the website problem that contributed to the duplicate payment was additionally obscuring of my account. A $ XXXX payment- noted in the account summary, was not subtracted from Account Due total. Since I was eager to avoid high finance charges, I called customer service to be sure I was paying exactly the correct amount to qualify for NO finance charges forward. For over 25 years I have paid my credit card in full, but discovered that once late payment triggers " XXXX cycles '' of finance charges on exisiting purchases. 
If the website had shown my accurate balance due in a clear way- and if it showed an identical payment already made when the customer service agent manually entered the duplicate ( the website was not accepting my payment from my XXXX XXXX XXXX acct ) - this mess would have been avoided. 
Obviously, there is no incentive for CitiCard to monitor OVERpayments ; holding my {$9800.00} 'hostage ' is clearly a boon top them if thousands of customers are treated similarly. 
There is an easy technical solution- can you make them fix this? 
If you require documentation of my difficulties- I am happy to submit all records & names of customer service contacts. 
Thanks for your attention to this matter. 
