if you dont pay within 7 days, you are classified as an "alternate user", and the price doubles.
That's exactly it, there is no obligation to get an invoice to you within 7 days or anything like that, the onus is on you as a non etag holder to ensure payment is made. If you do not the price increases to nearly double. SANRAL are also under no obligation to get the bill to you in any sort of period of time however the debt would prescribe after 3 years as per any debt.
So that gives SANRAL 3 years to get onto you by whatever means it can legally utilise.
Using the roads is a tacit agreement to these terms ...
whatever happens its going to be interesting