False advertising

Shaw academy was running a free course which was running for 4weeks where u basically have to watch a video and do a quiz afterwards but when I got to the last one I was told to pay R499 to get a certificate which I immediately send a email regarding false advertising and to cancel everything which I was only two weeks within the 4week period by the end on April a deduction goes off of R399 and I've been emailing them regarding to why they deducted they said they will investigate it's been 5 days and nothing . I've been going back in forth with them and there false advertising Charne