Earlier quoted context omitted.
To inject some expertise: "Enforcement of Judgments in the United States: Overview" https://uk.practicallaw.thomsonreuters.com/w-034-2858
Thank you! this largely agrees with the link I posted 7 hours ago. Particularly relevant, is that if you want to collect in the US, you have to go to the courts in the US and show them the foreign judgment. There are many circumstances where these are not accepted. >Juppor is talking about suing in Florida courts. Florida is absolutely at will. He may be able to sue to collect a foreign court judgement instead
If they are trying to avoid payment it will kink any activity in the EU, all over a relatively paltry sum.
The lesson though is that if you're dealing with potential shysters, like NFT promoters and other dodgy stuff this firm is doing (who else pays 70k Euro per year plus commissions to telemarketers??) then make sure they have assets in your jurisdiction that you can put a lien on, and ideally require cash up front.