I signed up with Jumpspeak, tried it, and it's no better than, say, DuoLingo (which is free). The Listening exercises play a short sentence, then you have two options about what was just said. It's a pointless exercise, as even if you understood nothing in the sentence, there's one obvious answer, and an (AI-generated ?) obviously-wrong second answer. Or, sometimes, they just show the correct answer a second time, so both options are correct !!
A nice looking app, but completely pointless.
The only positive thing I have to say is that I requested a refund, and they processed it within a day.