I've googled the Arabic a, and I cannot find any reference to that letter being described as ayin. If you can send me a link showing that, I'll add it in as a type-in.
I actually live in the middle east and can read and write arabic and I only got 15/28. Please accept more spellings like alef for alif, jeem, seen, and sheen for jim, sin, and shin, ain for ayn, ghain for gayn, noon for nun, and wow for waw.