Steering Failed problems of the 2011 BMW Z4

Eps failed while driving on state highway. Power steering alarm came on and steering became very stiff and hard to steer. Pulled off the road and turned car off and back on. Fault reset but the alarm ocassionally still sounded. Took to BMW service, checked out and said the eps box needed replaced. Dealer serviced car and continued to drive car for five months. This time steering failed again while driving , but the steering returned. Headed to home and steering again failed and alarm came on. Steering now is stiff and cannot drive. There was a recall (12v3002000) Nov 2011 through 2012 was recalled. My car mfg in oct. 2011. So BMW said our car was not covered. I feel BMW should look at earlier cars as this is very dangerous. If my wife would have been driving the car when this failed she would not have been able to overcome the steering failure. First failure at 74,000 miles.