Cell C - *********** service non provider

I received an sms on the 19th of December from this *********** service non provider stating that thwy are going to deduct my subscription on the 21st. I do not understand this as per our agreement they would deduct on the last day of the month, because this is when I receive my salary. There was no obtion provided not for them to do this, only for any queries to phone 084135, which I did. Why do I need to contact them for them not to breach our contract? At 14:02 on the 19th I made the effort to phone them, go through all their press this and press that. I spoke to a guy that, after I told him about the sms and that I only receive my salary on the last day of the month, he still asks me how he can help me. Eventually he said he will make a note. You will never guess what happens next. On the morning of the 22nd I get a notification that Cell C made the deduction. So, they did not lie when they said they will make a note not to deduct on the 21st as per their sms. They now went and deducted on the 22nd. *** Who is going to be responsible for the funds not available? Surely not Cell C I have 4 contracts with Cell C. I am not going to renew any of them. I will move them one by one to other service provider, as soon as they expire, which luckily for me, is not to far from now.