WHAT!?!? Don't toss it all!
Go get a bar tender style bottle opener and start gently relieving the pressure. A normal bottle opener will work too, but it's easier to deform the cap by accident. You don't need to open them all the way. Just gently apply a small amount of force opening the bottle, but stop before you deform the cap, so don't actually open the bottle. The excess CO2 will escape and the cider will begin to foam and rise. Released the pressure on the opener and the cap will tighten back up. You will need to do this a number of times before the cider stops foaming excessively. It will eventually.
If the yeast are still consuming you need to do this while they're being chilled so you can get ahead of the process and then pasteurize.