1999 Toyota Sienna brakes problems

1999 toyota sienna 56000 miles ,, we were driving at 60 MPH on I 294 south and the brakes completely failed ,,,my wife kept pumping them and lost control , we hit the median and the car rolled over thrice and ended up stopping on the roof ,, me, wife and two kids were safe by the will of god ,, all inseat belts ,,had gotten oil change ,routine maintenance 13 days ago ,, still have the receipt from jiffy lube that says brake fluid okay ,,, we are scared to drive any car now.

Driving on highway at 65 MPH applied brakes and the pedal went to the floor -- no braking occurred. Happened once before on a city street. Seemingly random failure which the dealer says they have never heard of and have no knowledge of how to fix since it's intermittent. Nothing has been changed since everything is supposedly working correctly. The dealer wants to see the car again if the problem occurs again -- but the car might be totaled by then - -hopefully no one will be hurt.