Bad Aftersales customer service experience

I have not been receiving good customer service from your team I was first charged for a Rewards programme I did not agree to. I then raised this with your team someone by the name of Lerato. She then mentioned that I am not being charged for the companies admin fee if my date of pay falls out of your company pay dates. I even asked her on multiple occasions on the correspondence I had with which are the correct dates to select she ignored this and now I have a new statement which I have been charged an admin fee for after confirming with your team on which date should I change my direct debit too. Now I am not willing to make any payments until this is sorted and resolved as I am now getting the impression that this now means I will always have hidden charges being added than me paying for what I signed up for. I have been patient with your team to sort this out however they have failed, Therefore I am now raising this hear and hopefully someone can help me as clearly your staff are not willing to be proactive and resolve complaints