Disappointed at the service where my grandmothers money hasn't reflected

I withdrew money on 02 April 2026 at old mutual ATM. I received r600 instead of r2400. And the slip stated that 1400 was dispensed. I wrote an email and they said they will get back to me within 7days which the 7 days was yesterday. The case file no is CD-252175 . It is my grandmothers card which she receive sassa grant at. Her name is hlongwane mphemphu. You can get ahold of me at *** if you are ready to send the rest of my money. I am very disappointed at your service and if you do not assist me, I'm willing to open an account with another bank. I am giving you 48 hours.