Yes my own blood brother was a victim of the same Diamond Bank ATM Machine. His own case was much higher than that of the poster (N100,000). He reported to the bank and they asked him to lay a formal complaint on the matter.

After a few weeks they wrote to him, stating that it is regretable that he actually withdrew the money in question, but rather took a step that could damage the "good" reputation of the bank.

The part that pained him most was not the money he was losing, but the fact that the bank's reply was sort of alleging that he actually wanted to do something dubious.

@ OP, its a pity. hope they get to refund you finally.

it may actually have dispensed it and somebody else took it.

someone once went to withdraw and lo and behold 15k was just lying at the cashpoint of the ATM. obviously, someone had inserted his/her card earlier, ounched and then waited for the money to come and left after sometime when it was not forth coming, only for the money to come after the person had gone and really, no card was in the ATM, costhe guy's card just entered freely.

all na ATM wahala

I use diamond bank and have had the same experience before but never got back my 5000 naira.

most of their ATMs don't work. the worst is the one off Adeniyi Jones ikeja.

if you're lucky it work onece in three trials to the extent that some complained to them about it at an exhibition in abuja
too bad

Ok

Its so sad that this problem happens everyday and there is no governmet authority to report to, you are at the mercy of the criminals (banks).
I fell victim last week thursday, bankPHP branch located @ ijaiye area of lagos to be precise, i needed to pay for some goods and i used my intercontinental atm card on the machine, N40000 was not paid to me but my account was debited. I went in to complain immediately and i was told d transaction will be reversed within 24hrs, today is the 7th day, i'm still expecting.
Is there no agency one can report to beside banks that can handle these kind of case swiftly? I'm not comfortable having a fear that i might loose my N40000 to a bank just like that. I'm really down at this moment.

I have experienced similar problem before but with different banks. They promised to credit my account within 24 hours. And the promise was fulfilled
I believe you will get a refund.