Immigration South Africa has:
Under the new legislation, the maximum sentences for contraventions are significantly increased. Foreigners who overstay their visas will automatically become ‘undesirable persons’, and therefore ineligible for entry into, or status in or even the ability to apply for a visa to enter into, South Africa. For an overstay of 1 to 30 days the person will be declared undesirable for a period of 12 months, for a second overstay of 1 to 30 days within a 24 month period the person will be declared undesirable for a period of up to two years and for any overstay of more than 30 days the person will be declared undesirable for a period 5 years. Multiple transgressions can also affect the length of the prescribed ban.
For someone that requires a visa, after the end of any ban a visa application must be made. Whether or not a visa is granted in such a case is, as always, up to the issuing authority. Given the shambles that administrative procedures have become in South Africa there is reason to suppose that a ban would have little or no impact on the chances of being awarded a new visa – there are simply far too many people being caught up in incompetently introduced technicalities. Being termed 'undesirable' by South Africa and actually being unwelcome to return there have become divorced from one another.
A ban is an official or legal prohibition. A ban for a year means no return for one year – and says nothing whatever about anything further after one year. It might be a "black mark" (or in these circumstances more likely a slight smudge) on one's track record but after the year has elapsed expect a return to 'normality'.
In fact if their legal system is less inefficient than their legislature, it could be that before the ban has been 'served' it is rescinded.
The revised regulations may be seen here and there may be fines (Section 39.) but no mention of any additional sanctions.