Chargebacks don’t work the way people think they work.
Under the hood raising a chargeback means your bank send the acquiring bank a message (with an exponent and evidence) that immediately reverts the original transaction and transfers money from the acquirer to the customers bank.
The merchant via the acquirer can then issue a message that does the opposite, again with an explanation and evidence. Eventually the card network steps in and makes a final decision, but they charge a significant fee to do this, strongly encouraging the parties to resolve the situation between themselves.
More importantly there is no “win” message or “give up” message. Instead there’s a set period of time each party is allowed to send a reversing message, after that time period the last person to send a message “wins”.
The periods of time involved are significant, ranging from 30 to 90 days depending on where in the process you are. As a result the bank could well say they’ve given up on the chargeback, and allowed the merchant to win. But the merchant can’t be sure of that until the countdown timer on a reversal has expired.
To make things even worse, most bank employees have no idea how payments actually work. They may well be looking at a tool that says they’ve “reversed” the chargeback. But under the hood that could just mean their system won’t send any further messages, allowing the other party to eventually win.