"Todg" is right.Chinese herbs help to break up stones. Also drink up to 1 Litre of freshly pressed apple juice per day for 1-2 weeks before the flush. Malic acid from apple juice helps to make stones soft.
My 1st GB flush was as unsuccessful as yours. You should do at least 6 flushes every 2-3 week to feel better. I did 4 and feel miles away I felt before!!!