If you just replaced the blades on it try turning the bolts around the other way and see if that helps. I sharpened the blades on a buddies Jiffy a couple years back and had the same thing happen when we went to use it. Couldn't figure out why it wouldn't cut as I had sharpened the blades before and had no issues. One way the bolt head stuck out to far and prevented it from digging into the ice and it would just bounce around on top. Turned the bolts and she cut like no tomorrow...
Edit: Forgot to add you can use a fine file to sharpen the chisel point if needed, very quick and easy to do yourself.