RE: Frozen Servo?
Most people would have the natural curiousity to attempt to manually rotate the servo back into its proper position. I'm surprised you didn't try that.
Anyway, you committed one of the cardinal sins of R/C: ALWAYS turn the receiver on last and off first. If you don't, the receiver will respond to whatever it thinks is a valid signal, and if it thinks that signal is telling it to overdrive the servos and break them, it will do that too.
What happened is that the interference caused the receiver to drive the elevator servo beyond its limits. You may have to remove the servo and take it apart. Worst case, there are some broken gears inside the servo.