URGENT URGENT

I made a payment to an incorrect account at Thyme bank this morning (A large amount) I then phoned the bank to please stop it. I was informed it was basically my problem now they cannot reverse the amount as it was an immediate payment

IT WAS AN HONEST MISTAKE. AND MY BANK DOES NOT WANT TO ASSIT ME

HOW CAN YOU NOT ASSIST EVEN IF IT WAS A IMMEDIATE RELEASE AND DONT TELL ME I MUST READ THE TERMS AND CONDITIONS