Well.

1) If you're in the U.S. just open a complaint with your State's Attorney General, because if you've been hit, many others have too.

I'd also open the same complaint in the State of domicile for the company, if it's a U.S. company.

2) Start a PR campaign, appearing on Radio, TV, Podcasts, speaking for Meetup groups, taking about the bank + any parent company + also any countries involved.

This includes for major shareholders in the bank or parent companies.

Create enough press where revenues drop off + you'll get your money back.

3) Lease a server from OVH (no U.S. connection) + setup a Website about this problem.

Then place an offer of sale on your site for $1,000,000 USD, so the bank + parent company's have a clear indication of how... displeased... you are with their business practices...

4) If you've never done this before, hire someone who has to walk you through the process.

Here's what you can do;

Gather Documentation:
Keep your receipt that shows you only withdrew $200.
Take screenshots or photos of your card records that show the $600 withdrawal.

Contact the ATM Provider:
Find the customer service contact information for the ATM provider.
Call or email them, explaining the situation clearly. Provide all relevant details including the date, time, and location of the ATM transaction.

Contact Your Card Provider:
Get in touch with H&R Block Emerald Card customer service.
Report the incorrect charges and dispute the transaction. Provide them with the same documentation.

Follow Up:
If you do not receive a response within a week, follow up with both the ATM provider and your card provider.
Keep a log of all communications, including dates, times, and the names of the representatives you speak with.

Escalate if Necessary:
If the issue is not resolved, consider escalating the matter by filing a complaint with the Consumer Financial Protection Bureau (CFPB) or your local financial regulatory authority.