debit that was not supposed to go through

hello,<br> <br> Theee weeks ago theres a company that called me selling their products then I was interested over the phone, after the call I went to their website and I realized that this is not for me, so I sent them emails i even tried to call them but the was no one answering, so I sent an email to FNB care so that they can block the transaction, then they told me I have to give them reference or customer name, but by then I didn't have anything, someone said i can block it myself, now i saw a notification of a debit yesterday and went online to try and block it, but this morning I got a notification that it went through, I blame FNB for this because I told them to block the debit but they didn't do anything about it to protect me, their interest is not in protecting us but to charge us, if they were here to help they were going to stop because they getting email from me as a customer, I should decide what I want with my account, what should go in and account, but they don't get it. I want my money back.