DSTV debiting unauthorised Showmax premiums from my account

Being a premium subscriber, I took advantage of teh DSTV offer and joined the free Showmax subs ****il March 2019). Lo and behold I noticed my premium for Feb was R300 more. Now again for March, R99 more.On queryign that today, I was told that I was charged for Showmax and that I had to link the accounts to ensure that I was not charged. Now, I went through the DSTV app in the first place to join Showmax. My debit order for DSTV was increased so how, if I had not linked the accounts, was DSTV able to debit my payment for R300 extra?! I am so angry! I have checked on Showmax and the accounts are definitely linked! Showmax confirmed via chat that they are not charging and that I should check with DSTV. Now the operator at DSTV did reverse the amount, but I want answers and assurances that more money will not be *******ly deducted from my account, and that I will be reimburesed FOR ALL the amounts!