Early Debit

On the 12th of December 2015, I was flabbergasted to see an early Debit Order going off my Account from Finchoice, upon calling them to enquire, I was advised that I was suppose to respond to an sms that they sent around November, my question is, the fact that i didn't respond to that sms, wasn't it clear that i didin't want to change my Debit Order date for December? And also, Finchoice didn't send me any airtime for responding to that sms, where did u expect me to get the airtime from? The stupid agent kept telling me that I was obliged to respond, how so because they know my debit date? And he kept telling me that i agreed to the debit order mandate which allowed for them to debit my account early, upon requesting proof for my perusal, he wanted me to hold on so that he can consult his Team Leader, I then advised him that I don't have time for holding, and requested him and his Team Leader to call me, he then promised to call, to date, I haven't received any call from them. Your service sucks!!!