I import products on a regular basis and I can tell you from hard learned personal experience that the best route is to get a freight clearance company handle it for you.
You are already going to be charged storage fees for the period that the bike has been standing there, and when it comes to the customs docs, if you don't fill them in 100% correctly they will simply reject them and you have to start over again.
They are also not particularly helpful with filling out the documentation if you try to do it yourself.
The freight agencies all know the process and will sort you out pretty quickly. Their costs are normally around R700 for handling the process for you, plus of course whatever storage, vat, etc is applied by customs.
If there are no dogs on the forum that can help you, then give Sanjay a call at UTI Durban on 0313106077 and see if he can help.
P.S. I did see that you have an agnt, but if nothing's happening then it's time to change. No?