Taking away my cover for which I have already paid and *****ing me over with my new premiums

<p><br />I'm in the process of buying a used car from a private buyer and I have finance through Wesbank. Yesterday I was in communication with Auto & General regarding the cover for my new car. Since I still have my Opel Corsa Utility insured with them they were able to give me a discounted premium (see attachment) of R687.72 that is including the broker fee. Since then it turns out the owner of the vehicle informed me incorrectly as to the model of the vehicle (2010 Subaru Forester 2.5X A/T) and Auto & General also made a mistake on the VIN number of the vehicle. When I phoned them this morning to correct the letter stating the confirmation of cover for my 2010 Subaru Forester 2.5XS A/T (correct model) they said the premium had to be corrected for on the new model. Since it was a higher end model and the value is more I asked them to insure it for market value and not retail value like I had before. It turns out the market value of the XS and the retail value of the X is very similar R189500 - R189800 but now they couldn't give a discount because I don't have any other products with them. They want to charge me roughly R50/month more for insuring roughly the same value of the car. This is worrying because I still have my 2007 Opel Corsa Utility insured with them so I should qualify for the discount. I informed A&G yesterday that I'm planning to sell my Opel at the end of the month and since I've already paid the for the cover for the rest of the month, that my cover could expire at the end of the month. Hearing from A&G that my Corsa is not even on their computer system anymore is extremely worrying because it means I'm driving around without cover for which I have already paid. Since my Corsa is still covered I should also still qualify for the discount on my premium. I want A&G to confirm for me that my Corsa is still covered until the end of August 2016 and to give me a premium that compares to the R687.72 that they offered me yesterday since it is cover for the roughly the same value on the Subaru.</p>