Complaint sub-issue: Credit card company isn't resolving a dispute about a purchase on your statement

I purchased a refurbished laptop from an XXXX  seller on XXXX XX/XX/XXXX and paid via XXXX using my US Bank Cash Plus Visa credit card. This laptop started to malfunction in XX/XX/XXXX but I believed the issues had been resolved. The issues returned in XXXX XXXX and intensified. I called an IT service professional, who upon opening the laptop discovered a faulty hard drive as well as a malfunctioning fan. He was unable to close the laptop up again and cited poor workmanship when the item was originally shipped to me. I use my laptop to work and had to find a replacement. I contacted the seller through XXXX  who ignored my messages. I contacted my credit card company on XXXX XXXX to launch a dispute against this seller and claim a chargeback for the full amount. On that date, I was given a temporary credit for the full amount and told that an investigation into the dispute would be launched. After 3 weeks and receiving an email telling me that my case was nearing a resolution, I called my credit card company again. I spoke with a representative who advised me that my case had been resolved and said it looks like were going to be giving you back the credit for that transaction. I was very relieved to hear this. However the next day I checked my account and saw that the credit had been reversed and I showed as owing the full amount of {$480.00} for the transaction for a faulty product. I again contacted my credit card company to inquire as to the reason for this, and was told that because my dispute more than 60 days after the transaction they couldnt give me a credit for it. I pointed out that a ) this had not been mentioned to me when I launched the dispute and b ) the dispute should never have been accepted if that timeframe is their policy. In addition I pointed out that I had been told by phone that in fact the credit would be applied in my favor and that as this was in a recorded phone call then the company had to honor it rather than just saying that it was a mistake. I was told that the matter would be investigated. I then called XXXX to see if they could intervene, as they have a window of 180 days within which to initiate a dispute. I was told that I had missed that window by 11 days and so they were unable to help me. If my credit card company had told me accurate information on XXXX XXXX I could have contacted XXXX and launched an investigation that would very probably have resulted in a ruling in my favour. Today I called my credit card company once again to enquire as to the status of the investigation. I was told that the representative who had told me incorrectly that the credit would go on my account was being given coaching so as to not make similar mistakes in the future, and that my request to apply the credit had been denied. I asked why I hadnt been immediately turned down for the dispute on XXXX XXXX and was shut down immediately with a comment of youre free to take this up outside the bank. I said that I couldnt go to XXXX as a direct result of US banks incorrect information as their window was now closed to me. I was told once again that my request for credit was denied and that I would have to resolve the matter outside the bank. The entire chain of mistakes was caused by US bank Visa and they have refused to admit to any wrongdoing or apply the credit for an item sold by an unscrupulous seller.