I know how SARS works I'm afraid
That's why you need to contest or contact them if you receive correspondence stating you owe money. What I was referring to is if you do not do anything about and just leave it then they will take what they want, as an example if you have R500 in your savings account and you owe them R800 for late submissions they will take that R800 off your bank account / pay regardless of how much is in your physical bank account. That means you'll have a red balance of - R300 in your bank account which you now will be fined / or pay heavy overdrawn fees.
SARS are ruthless now my friend - they cracking that whip hard this year, even if you owe them R10 bob !! they coming for it.