Product: Credit card or prepaid card

On XX/XX/2021, I made a remote purchase with Chase Freedom credit card. I paid {$480.00} with the card, then bought some items from the XXXX XXXX XXXX store. However, the merchant sent the item to the wrong address, and I didn't receive the item. Then the item was returned to the merchant. At first I couldn't reach the merchant because the sales assistant who helped me left the company. So I disputed the charge, and got a temporary credit. 

After some days, I finally got in contact with the merchant. They confirmed the returned item was received and will issue a refund for me. In this case, I immediately contacted Chase, and cancelled my previous dispute. And my account got recharged for {$480.00}. 
However, after a few days, the merchant says they failed to do a refund because the fund is charged back because of a dispute. They accepted the dispute. Im surprised because by the time when they processed the refund, I had already cancelled the dispute and got recharged. 

Then I contacted Chase customer service and told them the whole story. At first, they asked me to fax a written dispute statement to reopen the dispute. I did so and faxed the letter to Chase on XX/XX/XXXX. This is the first time I requested to reopen the dispute. But two weeks later, Chase replied back and refused to return the money because they think its a valid charge. Then didnt explain any reason why they think its a valid charge in the circumstances the merchant already accepted the dispute. 

Then I called Chase customer service again, three times. The first representative said this charge is due to open a dispute. She said I have 90 days for a dispute, but in fact I called them in early XXXX, its not even 90 days. She hung up on me when I pointed this out and requested to talk with a supervisor. The second representative said I need to provide evidence to reopen the dispute, and confirmed its not due to dispute the charge. To double check, I called the third time, and the third representative said the same with the second representative. Then I faxed the written dispute statement to Chase immediately, along with all the evidence ( the email between the merchant and me, including all the content the merchant confirmed they received the returned item and accepted the dispute ). 

I faxed the second dispute statement on XX/XX/2021. However, two weeks later, I got a response letter from Chase again, stating that they confirmed the charge is valid, with no reason again. Because I'm a private client of Chase, I made my banker contact their credit card department, now they say I only have 60 days to dispute a charge. They can not do anything now. But the first time I requested a reopening dispute, it was within 60 days. And when I made the second fax, no custom service ever told me this 60 days dispute period and made me request again. 

So far, I still have no clue where the fund is. Chase didnt provide any proof that the money was sent to the merchant again. I reasonably think Chase just doesnt want to, or even their system just can not, reopen a canceled dispute. I heard several similar cases when I post my experience on internet. So Chase is just delaying the complaint again and again and making it past due so that they dont need to do anything to resolve the issue. I need them to handle this case appropriately and return the money to me.