Approved isn't what you think it is!

We own a small independent workshop specializing in the servicing of Porsches and all the major car brands. We have had all our banking business with FNB for well over 10 years, and during this time there has been a gradual decline in the service. Today however, has us wondering if we should actulally keep our business with FNB! Yesterday a client paid for the repairs to his vehicle with his card and the amount of just over R51,000.00 was approved and card slip for both the client and merchant stated approved. We uploaded the batch and the card machine printed the slip for the day's transaction and it stated successfully uploaded. Image my surprise when at 11:15am I received the settlement report via email and the amount of R51,000.00 odd was rejected!! I immediately contacted FNB Merchant Services and was told by the lady in the fianance department that when it is a large amount like this the bank needs to verify the transaction and this can take 10 to 15 days. I asked her why then was the transaction approved if it needed to be verified. Surely it should have been rejected and an authorisation request needed to be made before I released the vehicle to the client. I asked her, what if the transaction is not verified because then I will not only be out of pocket but I the client might be long gone. No need to worry, we will trace them she said! I told her that this was totally unacceptable, as the funds shoul be in our bank account because the transaction was approved. Not being able to provide a satifactory solution she fobbed me off to the technical department who repeated the same story she gave me about the large amount needing to be verified. I asked that the matter be escalated to the team leader / manager and I am still waiting for someone to contact me. Who does FNB think they are that they can hold onto our funds when they, FNB have aproved the transaction. Is this type of behaviour not indicative of the state South Africa finds it self in - ******* to the core!