If a SIM has been locked or deleted by Vodacom SA, this will be shown on the SIM list, as well as on a SIM's profile page.
SIMs typically get locked due to an extended period of no usage (active billing events) from the SIM. Each network has its own SIM expiry rules. (View Vodacom SIM deletion rules here).
SIMs may get locked by the network, as they are in line to be deleted. After being deleted the SIM card (ICCID) will become unusable.
SIM list page:
SIM detail page:
You can also view all deleted SIM on the SIMs page by filtering by "Network Status" = "Deleted"
Since the SIM has not seen recent usage, you may choose to suspend the SIM on SIMcontrol to make sure you don’t incur any further costs.