I just need them to cancel my payment, I don't need the money anymore

I have app**** for a loan on Thursday, I had to wait until Sunday for them to approve my application. I acquired a loan from other institutions and when I told them I dont need the loan anymore this morning they told me that they can't do anything as the money was sent to me. I told them I need to cancel but they refused telling me that the money would appear in my account anytime.