There is a clear warning in the readme file. Also, there was absolutely no need to run the update. Since you apparently even took the update file from the CD, instead of the website, it might not even have been an update, you may just have flashed the same version again, or even an older one (without paying attention to whether it said "Not Updated" or not).
I'm afraid the price is normal, as it is now quite complicated to reprogram these old cards at the factory. That is assuming it is really the old flat card - you still did not tell me.
This whole thing is quite unfortunate, but there is no denying that you made many mistakes in the process. If you make a mistake while driving and crash your old Renault 4 into a tree, the car company also will not pay for the repair, will they....? Even if you are an old customer. Desolé...
Regards
Daniel Fuchs
RME
Regards
Daniel Fuchs
RME