I subscribed to this thingy for R15 gift card and they went on and topped up my subscription without my permission and deducted R554,14 and now they telling me that they cannot refund me

I subscribed to this thingy for R15 gift card and they went on and topped up my subscription without my permission and deducted R554,14 and now they telling me that they cannot refund me. How when I never asked for a top up and yet y’all went into my account and deducted money that we never agreed on!!!!!! I’m totally not happy and I would like this matter to be looked into and escalated to the correct department and be dealt with ASAP