Payed for new part but used old part

My car`s ignition failed. Could not even turn over to unlock the steering wheel... Vaal Auto offered to fixed that aswell since they tow me aswell... The one person said that the selector pins inside the ignition gets stuck and the have locksmith equipment in there shop to fix it. The next morning the mechanic called to say that he have to replace the unit with the keys as it is a coded key. The coded key was apparently worn out with the selector pins. When I got the keys and the car, I tested the old coded key, the new coded and the old spare key and I started my car with all three keys. So are the old key really worn out? The old coded key electronic was build into the coded key housing and the ignition had the old marks where you insert the key... To me it seems the ignition unit was serviced and not replaced with new unit as I was told. The very first person told that the ignition can be serviced in order to keep everything original... After this I phoned a known Locksmith to confirm this....