Medical aid Discontinued for nothing

I am so defeated by this ******** medical aid, I called before a deduction went off this month to ask how much I would be paying since I added an infant and the call centre agent told me I would be paying the amount I was paying plus the new infant amount only and I asked him if he is sure and there is no pro rata or anything like that he said no there isn't, now I left that money in my account for then to debit and the lady today says the other guy I called made a mistake and the infant amount should be for November and December and I dont have that amount of money and the lady on the phone is saying they will have to discontinue my medical aid with them, how does that happen even