I use Candys (eggbeaters w/a small platform) on all of my bikes and yes, there is a lot of float in the pedals - my older knees prefer it over longer rides. The float and play also allows easy access when you ride in mud and dirt, which is what they're designed for. I also have Shimano Ultegra pedals that I'm currently using on a spin bike - night and day difference - the Shimanos are like ski bindings compared to the Candys.
I've been using mine for a few years now with zero problems on the spring - it should not come off (its not part of the rebuild kit, so I assume CB expects it to stay put and not wear out). If you still want to use the pedals I'd suggest returning them for a new set as warranty repair will take much, much longer. You just bought them - the store will take them back.