Some of these don't work very well. I got one that has smooth, shiny chrome plating on the underside of the foot. What kind of good could that do? It doesn't grip anything at all.
And you do have to find a brand that lines up with the feed dogs to get the best results. If you're using an even feed that's made for straight stitch on a zig-zag machine, you're not going to get the best results. (and vice-versa)
So, you may have had it on just fine, but perhaps the teeth on the even feed weren't lining up right or maybe there was too much or too little pressure on the presser bar? Mechanical stuff is only a little behind computer stuff in the number of possible annoyances they can give you. ;)