FNB reverse my R300 into my account

I withdraw R300 from a Standard Bank ATM-BP Makhaza this morning around 11:13since there is no FNB ATM at Makhaza(Khayelitsha) I didn't received the money from the ATM there a notification on the screen that the R300 was restricted. I was desperate for money as I needed to go to the dentist and take out my aching tooth and withdraw another R300.FNB I want you to reverse the R300 into my bank account as I only received R300 not R600.