So, the failed unit doesn't count toward the credit point, but the credit point of the failed unit will be included when calculating the GPA ? lol
Credit points are independent from your GPA. I'll try my best to illustrate this.
When you take a 6 credit point unit, you aren't awarded 6 points that you need to
keep by passing, rather you are working to get a pass minimum to
get those 6 points. Meaning even if you enrol in 8 units for a year, you still have 0 credit points total until you pass them.
An N grade in a unit is worth 0 credit points, and 0.3 grade points. See how regardless of not being awarded credit points, you still have grade points that need to be accounted for (and same with WAM).
If your circumstances are of a nature that may make you eligible for special consideration to possibly get a withdrawn incomplete (WI) grade, please try to look through this avenue before exams begin. You won't receive credit points as normal for a WI grade, but it won't be calculated as part of your GPA.