Cashbag no longer working, and they don't respond to correspondence sent

Cashbag used to work well, now it doesn't. I have the cashbag button on chrome and when I use booking.com I always apply the % discount from the cashbag button. I have booked a number of times in the last year and a bit but I am still to receive my discounted cash back. So to put it simply, this is a waste of time.