Unicef — auto deduct amount unicef

Unicef came to my company and i decided to donate for a noble cause, my bank account details were taken and since then every month an amount gets auto deducted. I want to stop the payment. When i called my bank they informed me that it has to be done from unicef. I called them however i never reached an individual.
Making a donation is a personal choice and not a forced one however unicef is full of frauds. Should not have believed them.