FINCHOINCE...U ARE REFUSINGTO REVERSE A LOAN I DON'T WANT YOUR MONEY

Today I did a short loan under the impression the loan is interest-free because that was communicated by SMS to me. However upon realizing that there's still extra fee which they charge I canceled and asked that they please reverse the money. They told me that they have already processed it but I asked for them to reverse the process and they dropped a phone on me, RUDE!!!. I only receive the money now into my account at 16:00 This was around 11 am in the morning when I asked them to reverse it. How can I make sure that they don't charge me for this money because I have asked for their bank account but they haven't given me?