How this is different from this scenerio: Think you send the money for mortgage payment from your brother account who doesnt has any financial relationship wrt

How this is different from this scenerio: Think you send the money for mortgage payment from your brother account who doesnt has any financial relationship wrt that mortgage (by mistake).. Plus you pay for whole year in one transaction incl interest. Can you go back to bank (lets take Citi for simplicity) and ask for money back and telling that you will send for one month only with right account. How will Citi react?