I am sorry that you are having difficulties with your sellers. Respectfully, as I posted in another thread (and will shamelessly almost verbatim copy and paste here) this may be a blessing in disguise.
DVC's value is in trips that are booked 7+ months out. If you can make a trip inside that work great, but the default mindset should be trips that are 7 months or more out.
Also, rushing to purchase a resale DVC just to possibly be able to book for a trip in August (besides being almost impossible) could lead to a decision you regret. I understand the notion of wanting to put your trip money towards DVC instead of a hotel/rental, but I'd focus on going next summer if that's what you're looking to do. If you're set on this summer, I'd look at renting (which will be very difficult at this stage, besides maybe SSR) or a hotel.
UPDATE: Just stalked the RAT for fun (yeah I'm a pretty wild and crazy dude).There's actually great availability (as long as you're flexible on room type and exact dates) at OKW, BWV, BRV, and AKV (and of course SSR) in August. You should definitely put in a rental request if you're set on going in August.