Standard Bank Broken system

I don't understand this Standard Bank. thy deducted money out of my fnb acc for my standard bank credit card ( and i understand the rates and all ) but in this case its not the rates. its there system that is broken.

Standard Bank deducts money from my fnb in dec i was a little short ( my fault yes ) i did not transfer money from my savings to my main in time but thy deducted it any way resulting my account to be in a - ( that's fine i understand )

2 days has past and i see my FNB account is no longer in -. so as festive season traveling and visiting families i went on my standard bank app to see if there is money. and SUPRIZE yes thair is money. so i used the money and now standard bank says i should have waited 48hours ????? why???? if there is money in my STD credit account and i need it then??? i mean they getting the rates and stuff like that so its me who is loosing... yes. but now they say i need to pay a double payment in January 2020.

i don't understand how is it my fault that standard bank system is broken. how can you deduct money and if it failed then HOW THE HELL CAN YOU TRANSFER MONEY TO THE ACCOUNT????

( customer bank ) ------> ( standard bank system ) -----> ( customer account )

this is how the money gets transferred so if standard bank system did not receive the money HOW THE HELL CAN THY PUT MONEY IN MY ACCOUNT??? and i'm the one to blame for this? and i'm the one that is suffering for there mistake and broken system???

NEVER eva trust standard bank no mater what this is the 999th problem i had with them and no more!!!