No feedback/Feedback after lodging a complaint

After lodging a complaint on behalf of my sister, she received a call on 13 April (Monday), reassuring her that she will be updated with every progress regarding the resolution of her *****ently withdrawn money at an ATM, the same day I received an email from the above, requesting my sister's account number, which I forwarded, however to date, no one has had the decency to call or update anyone of us with regards to the progress that bear expected outcomes for my sister. According to the caller who called my sister of Monday, she reassured her that this matter will be resolved by today.Disgusted