Cash back Expiring every month now!!!!!

So clicks cash back now expires every month.!!!Every month it expires and one loses a couple of Rands since when. I usually collected points throughout the year and and use my converted cash at the end of the year.. But this year I have been loosing my cash back money every month I get an sms that it expiring if I don't use it and it does get deducted. I sent an email about this the response was it expires once in December but I just another sms now that R20 cash back is expiring from whatever balance I have on the 23rd of September and it's going to get deducted, saving my cash back is a mission time around.. What is happening Clicks.. Can someone explain I haven't used my cash back this year but it keeps decreasing every month 😠