withdrawn cash

I went to a nedbank atm on the 25 November 2015, I withdrew R3000.00 and R2000.00 on the 27th, I made statement on the 29th I was shocked to see that R2000.00 was withdrawn on the 26 same month.I went to southgate branch a an atm ***** documents were filled and advised I will get a response in 6 to 8 working day.No one called I went back yesterday my request was declined.I want my money because the notify service was not working and how will I know when your ATMs are tempered, I bank with this bank for 18 years now .