OK, I have a S400 and have tried all the methods of bringing back my memory card; has anyone called Canon for help? Anyone have their number?

This is exactly why it's wise to use several cards, rather than one large one. Reason being, insurance. Any memory card can fail or become corrupted. And when you're on vacation the last thing you want is to lose the opportunity to take pictures until you can recover that media card with a software utility. If your card goes bad, swapping another one for it at that moment is of advantage so you can keep taking pics.

Then, later when you're in front of your PC, you can use a utility like "F-Recovery" to get back your pictures and recover your card.

No need to lose the moment because you relied on one card one when several can solve that problem. At the very least, you want to get more than one of whatever size you settle on.

Try F Recovery. There are others, but that's the one I've had good luck with.

Absent that, it may be damaged beyond repair. But I wouldn't give up.