It's some trouble, but a quick filing in your local small claims court for the $700 would be an interesting way to get your money back and see how it plays out.
In a dream world: find a law firm that buys the class action from you. Given their market share and the amount in question, it should be a profitable affair.
Meta-idea: create a startup that functions as a marketplace for bringing together ideas for class action lawsuits and law firms.
Not quite the same thing as what you mentioned, but by creating financing that evaluates cases by their potential for a payoff, this should seed the kind of marketplace you mentioned.
Most likely. And in any case, most small claims courts don't allow the representation by counsel, and as such they're more lenient about complaints submitted. File, serve Team Viewer, show up on day of, collect default judgment or argue why lifetime means lifetime.
TeamViewer appears to have a US presence (and likely, assets worth at least $700 plus small claims costs for seizure by the Pinellas County sheriff’s dept) in Clearwater, FL. Probably not local to OP, but more local than Germany (where TeamViewer is HQd).
That's not correct, they have a US presence and sell in the US. You can't be judgment proof just by headquartering in another country, any US assets can be seized to cover judgment amount. Take the judgment to the sheriff and they will literally go seize assets for you to cover judgment.