What study system works best for the EA exam when I need to turn review materials into passing performance quickly?

A real Reddit thread titled 'Not getting paid 2nd half of fee' raised an EA exam or tax-practice issue that deserves a clearer framework than a typical forum reply. I want the exam-ready or practice-ready version using the actual source signal rather than generic advice. Source context: I was engaged to prepare 3 years 1120 and 3 years bookkeeping for a non-resident of the U.S. who owns a U.S. corporation. Owner is German. I completed the work and took 50% upfront. I have a card on file that I will usually charge but the payment failed. The clients said he would wire the money. He has not. It’s been 4