SHOWMAX is not being fair for unsubscribing error

I am HIGHLY upset that Showmax will not assist. I was innocently browsing the various platforms for movies this morning (please bear in mind I only have DSTV access, as in this difficult time with the Coronvirus, we cannot afford anything more) and I went into Showmax to just see what they offer, it is very easy to get into their site, I was browsing and looking at their movies and charges etc, I went back into my online account to see my balance and decoder details etc (as I was thinking of changing from debit order to manual payment rather) and I saw that the subscription was activated for showmax of R99. I was so shocked, I didnt even realise that I had subscribed, no where did it ask "ARE YOU SURE YOU WANT TO SUBSCRIBE" as I would of ticked NO. But there is was, subscribed for R99. I immediately got hold of DSTV who gave me the details for Showmax who told me that yes I had subscribed and unsubscribed but that a charge of R99 will still go off as the system automatically does this. I will fight this as I made an error and why can we NOT cancel something immediately and payment be reversed, I dont want Showmax for a month, surely one can cancel a debit order, done by mistake, an hour later and they can CANCEL their service.