You don't need the key, you need another dealer. Ask them to try running it with the O2 sensors disconnected. Then figure out which one is bad, replace it and you're back on the road. The "key" they are talking about is for the full race ECU system, and it won't even work on your ECU if you're in the USA, you also need the "race" ECU. Your proof is that it was running fine before "something" happened.