Got text on runway telling me that our driver was on the way. I replied with landing status but was told that number that sent text could not receive reply. Instructions said to walk to Transportation Plaza, following the signs. There were no signs. Tried to call number for Customer Service - in Berlin, but got a recording. Walked around looking for car and license #. Hot and tired. Clicked on "CHAT." Got message that I was being connected. Minutes passed. Same message - no connection. Gave up and took taxi; cheaper - - and there. Never again.