Does not seem to be just you - my account (at another ISP) is hard-capped and I went WAY over the limit, last I checked it was still active (even after a router reset). Have switched to another account now (with spare GB left), so not sure if it is still like this.
Same "problem" here - I left the downloads running and came back to the PC now ... about 2gig over limit and still no visible capping ...
Not that I am complaining you know
there seems to be some problem with telkom's capping system in Aug, I basically used up 16GB on my 3GB telkom account
(come telkom, call me an abuser, I'll abuse ur account as much as I can)