FIRST CHECK YOUR WALLET AND CHECKING ACCOUNT.
Then take it in to a transmission shop for a diagnosis. Hold onto your knees so they will not rattle when they give you the quote to fix it.
It may need a transmission shift selector linkage adjustment if it found it's way into neutral all on it's own.
check your transmission fluid level
Since it only did it once, i would suspect you bumped it into neutral by mistake.
it happened only 1 time at a red light i was braked and when the light turned green the engine just reved up and didnt move i parked it and turned it off then on and it moved it hasnt done it since should i be worried my car is a 2002 mazda millenia engine was replaced not to long ago
