Surprise billing on forgotten account

Dec 15 i registered a showmax account. i had a 1 month free voucher, coupled with the initial 7 days, ~37 days of free showmax. I was reluctant at 1st as they require a full account set-up including bank acc details, but did it nonetheless. Not once did i have the intention of continuing with a showmax subscription. Then, after registering i tried unsuccessfully to stream any media from showmax, as a result of this i naturally forgot about the account, and can honestly say i hadn't once used it successfully. Suddenly i notice that after the 37 days i've been billed for one month. Now, the amount doesn't bother me, but the practice of immediately initiating billing without so much as a warning is against everything the CPA stands for. They can see on there side that i haven't used the system, but this doesn't stop them from billing. Companies like this are far too quick to exercise administering your account, but only to the extent that they benefit. They will never miss the opportunity to bill you, but don't even have the decency to inform you that billing will be initiated. The least they could do is check with you after the trial period, but that would require actually caring.