Very bad service, now agents are sending me from pillar to post

Good day I have just had a bad experience with this bank. So last week it happened that I made arrangements for my personal loan to debit double the following month (December). Today I received money in my acc & the loan debited & only today I was advised that the loan was tracking & the money can’t be reversed which is not mine 😩 how could this happen. Definitely closing this account