Money not refunded

I sent money to the wrong account by accident that was Friday the 22nd October 22nd and today is the 25th I was so Friday they could not help me I pursue the issue even further today which is Monday and I was told that they were sorry they could it’s nothing that can do to get me my money back and I think that’s total garbage the money is just sitting there in the account in the wrong account and I can’t get it back please help me pursue to get this money back I sent $100 to my granddaughter and it went to the wrong account. Refund my money which I did that and then I also canceled the transaction they bothered to do neither while the transaction was pending coming out of my account I called them and call them they never responded until the transaction was complete from my bank and then they said it’s nothing they can do so they took my money I would like a refund and I do have any and all correspondence