'On the road fee' and registration

I bought a Harley Davidson on 25 August from Harley Davidson Zambesi (HDZ). I paid cash for it and the sales person at HDZ ensisted that I pay the same day and send proof of payment the same day. The M/Bike was delivered the next day to my house. On the day of purchase I wanted the paperwork to take with me for registration. The sales person convinced me that HDZ MUST do it with an additional fee of R3900. I paid that fee and after numerous calls and emails am still waiting for the registration and outstanding items on the bike I do not know how to resolve this. Their exucse was that they were waiting for the bank to release the Natis document. Normally the bank will release the Natis within a day or two after they received full payment. The invoice is the only document I received from HDZ