I used Lufthansa's web complaint form to relate an incident last month transiting Frankfurt:

Arriving at a hard stand as a "wheelchair, can do steps" traveler, I was given assistance onto the normal bus to get to the termianal.

At the terminal, there was no assistance waiting. Another passenger moved my manual chair off and the driver came around to help me down and into my chair.

I rolled inside and presented myself at the disabled assistance podium just inside the terminal. An agent there directed me to "take the elevator" to get to my connecting flight. I made the mistake of thinking it would be an easy roll, but it turned out to be a very long transit that included barriers deigned to prevent carts.

After a delay of several weeks, here is the key extract from their response:

"A review of our records verifies that wheelchair assistance was sent to greet our passengers arriving at the terminal on board LH455 on January 23, 2010. The wheelchair attendant was waiting for you and announced your name; however, no response was received. Rest assured that it is our intention to get customers needing wheelchair assistance to their gates in a timely manner. "

That is simply NOT what happened.

Suggestions on how to escalate this matter?