I've posted on other threads about my experience with Primas. I finally got around to stretching out the toe area this weekend. It's a little better, but they are still tight. Here's what I did (and I'll do it more since I can't return mine either...):
take a hairdryer and soften the toe area inside and out. Do not heat up any other part of the shoe. Put on a medium-thick pair of socks, and stuff your foot into the prima. Heat again. Do all this sitting down, or you risk losing all shape and support in the shoe (I had previously tried the clothes dryer method used with other
crocs, and walked around the house...the shoes completely flattened out so I had to throw them back in the dryer to regain their original shape). Let the shoes cool on your feet, wiggling your toes and flexing your feet as they cool. After they are cool (about 5 min or so), take them off. Take your socks off and try walking around in the primas to see if they have more room. If not, maybe try a thicker pair of socks and repeat.
I'm going to try thicker socks tonight...