Edit; I know there are more reasons for chargeback and those you can get across the line here too, however, 'frivolous' chargebacks are not good for anyone but they are easy in the US.
My partner's parents were hit hard though, about €5k. They argued back and forth with the bank for about 6 months to no avail. "Sorry, we can't do anything" type of answers. The bank also tried to trick them into signing "fraud forms" that in the fine print absolved the bank of any responsibility. It was only after I actually filed a claim with relevant financial authorities, and then hit the bank with that that they suddenly got their money back.
The interesting thing is that this mentality is so prevalent that even the non-fraud department bank employees genuinely didn't know that the bank is supposed to actually help them. Many of them told us their own stories about how they were defrauded (I have no reason to suspect they were lying because they were family friends, and I heard the stories before our incident).