CAPITEC SUCKS AND CAN NOT HELP AT ALL!!!!

I have a loan with Capitec bank, I DO NOT HAVE AN ACCOUNT WITH CAPITEC. I called just to find out when is the last date of the debit that they take each month and they simply CAN NOT HELP ME. The agent I spoke to tells me I am lying about not having an account with them, but I DO NOT HAVE AN ACCOUNT and they still gave me a loan. How can i resolve this????? Now i have to go to a branch, which I DO NOT HAVE TIME FOR, but they just don't care, then they also take the debit order when there in no money in my STD bank account and leave me on a negative balance and i have to pay my bank as well!!! THEY ARE LITERALLY ROBBING ME