Apple magically looses my wireless card from my iMac!?

So I ran the Apple update on my 27 inch iMac and it stopped my Bluetooth from working so I sent it in to the iStore Canal Walk. So they ran diagnostics and they could pick up my Bluetooth and couldnt understand why it wasnt connecting so they sent it in to Core in JHB. 2 weeks later and they come back telling me that there was no Wireless card present in my computer. now how do i spend R40k on a computer and they tell me after doing their diagnostics that there is no wireless card present.

No one can give me a clear answer as to what the hell is going on and on top of it they want to charge me R2k for a wireless card that magically disappeared out of my computer?