ABSA ATM and client service

Went to cash with draw money from one of the ABSA ATM and I got R400 less than the requested amount, when I call them they told me to go to my own bank in order for them to reverse the money, my own bank is telling me that ABSA still need to investigate and it will take up to 30 days, if ABSA doesn't contact me after 30 days I must call ABSA again..... So angry with their faulty ATM and now I must suffer because of them