My brakes goes to the floor and making a groaning sound i had at the twice

I had a simmilar problem. It sounds like it could be one of your wheel speed sensors is bad. The car thinks one of the wheels is locked up so it reduces brake pressure untill it senses the wheel is moving agian but that signal never comes and the ABS computer reduces presure considerably. They should be able to test the sensor without driving it so don't worry about reproducing the problem for them. The fix is usually to replace the wheel bearing which the sensor is built into, keep any warenty paper work as the new sensors tend to fail quickly as well. If the problem occurs more often before you can fix it you can turn off the traction control which disables the ABS and Traction control. (just remember to be extra cautious without them)