U did the right thing. Quickly get a good workshop to flush it all out. Those lao cheow mechs will know what to do when u tell them the tranny is filled with wrong fluid. Very very troublesome process, but no choice. Then after a few rounds of filling n draining, they will change tranny filter with new gasket n proper atf ws fluid.
Don't mess with the tranny. Always stick to the recommended wtf oil. Toyota atf ws isn't expensive. Rather u spend 50$ than a few thousand to rebuild the tranny. Not to mention a few weeks down time.
My friend kena once. After less than 2 weeks, the tranny died. He scraped his ride.