So-called technical error or Incompetence

My sister and I upgraded my contract on the 27th of August 2022, and at the same, due to circumstances had the banking details changed from my sister's to mine, the consultant said that the amount would be debited from my account from the end of September, however, the amount was debited from my sister's account once again. On the 1st of October 2022, I again went to the KeyWest branch and enquired why it went off my sister's account again, although the consultant was helpful, she stated that due to a technical error, the banking details were not fully changed, she proceeded once again to change them to my details and said since it was already the first it would only go off my account as from November, again this past Saturday I again went to enquire, this time however they only picked up my account, I told them that it was changed on the 1st of October, they also then said reiterated the point that due to it being changed on the first it would only go off in November, however, that was not the fact and my account was debited. So now what? I am the one who is going to be doubly punished because of a so-called technical error or because of incompetence.