Audibear

Ignition trouble with key not able to turn on my A6 2002 2.7t. This will be the fourth time since buying, and dealer doesn't know why this failure. Cost to me over owning car has been significant. Last time approx. year ago they did cover labour on repair, but truly a frustrating experience. Have enjoyed this car and have just been searching for new, or even used Audi to replace, but problem just starting to show again. Not sure I want to go the Audi way again because of this. Can' t in all fairness sell this car to buyer till I've had it repaired.
Past experience shows that while trying to turn car on it begins to catch as I turn the key , and with slight wiggle engages the ignition and starts. Over weeks this may sporadically occur, and then has even turned 360, which is a very uncomfortable feeling. ( I've recently seen this post in AudiWorld forum, ... "My key did a 360 in the ignition! Weird and scary...the key rotated 360 degrees in the ignition and nothing happened! I removed the key, reinserted and it worked fine. Has anyone ever experienced this?"...). Tried to connect to this post but nothing yet. But, just as they found, by removing the key and then slowly trying to turn it, it will engage and start. This progresses to a time when it will completely lock up, and sometimes spinning, but not allowing me to engage the ignition to start the car. Even sometimes not allowing key to come out. Next step, the tow truck to dealership.

Please, Any help would be appreciated.