Rental assumed

I have regularly bought gas from Afrox shop (http://www.afroxshop.co.za/) and every now had issues. Like them stating on the invoice one amount and deducting another - this is not according to the Payment Association of South Africa (PASA) rules. I will forward this link to PASA as well. This time round, I decided to order a tiny Helium gas cylinder for inflating balloons and nowhere on their site they stated that apart from paying close to R1000 for the cylinder you have to pay R250+ per month for rental. When I queried them they stated that it is mentioned in their terms and conditions however this does not apply to all products. I have also escalated the issue to the NCC (National Consumer Commission ). I have now returned this half full cylinder to them. That is the end of my business with Afrox.