Ferris Bueller, this is some really solid feedback. Sorry for disappointing you.
Based on your suggestions, I’ve added a contact email to the support website. I’ve also explicitly called out that Rightspeed currently supports speeds between 1–10x.
As far as slower speeds, I think your suggestion for foreign languages is a good one. I’ll look into supporting this in future versions
Send me an email at firstname.lastname@example.org, and we’ll sort out your refund.