Fresh Crystals for cat litter (*******)

I bought 2 of the Fresh Crystals from them which i paid R419 for and on the website it says 30-40 days of freshness if you use the 2/3 of a cup on top of the litter. That is absolute *******. I even use a full cup and it does NOT take away any odours at all. I've used it now more than once on a clean litter box and not even hours later the box smells. The Crystals does not work at all

That is absolute waste of money!!!