What do you mean "blocked the quilt"?

after the quilting was done did you lay it out, measure it - sides, and diagonally to make sure it was all squared- trim as needed - then add the binding?
if the quilt becomes out of shape while quilting it is easiest to square it up before adding the binding.

You can sherr (not sure correct spelling) the edge. The effect is slight gathering of the edge. I've tried this on a wall hanging and the quilt was able to hang flat on the wall without the wavy edge

the last quilt I made did this. Washing it made it go away.

That's my thought, as well. If the edges of the quilt are larger than the measurement you get when you measure through the center of the quilt, the edges will wave, or, if you hang it, it will not lay flat.

you can also get this if the quilt center is quilted more densely than the borders. sometimes, if this has happened, i pull on the binding slightly when sewing it on. i emphasize slightly. this will take up the extra in the borders.

Another factor could be the grain of the fabric. If it is cut lengthwise, parallel to the selvage, it won't stretch as much as if it is cut the WOF, width of the fabric from selvage to selvage.

Wash and dry til damp. Lay it out on the floor with bath towels under it, then pat and pull all of the quilt into a straight line,until everything is nice and flat and even,and leave til completely dry. Maybe put something heavy on the four corners to hold it perfectly flat and straight. This is blocking.

Good luck

Is your binding straight of grain or bias? I found since doing my binding with a straight grain that my edges lay flatter. It's seems that the bias binding stretches either the quilt or the binding and I get ripples no matter how carefully I sew it on. I only use bias for doing scallops or curves.
It also helps if you can cut the long side borders down the length of your yardage. It does take more material to get the border without seams but there is less stretch down the fabric length. As others have mentioned, you can block your finished quilt to help your wavy edge.

Thank you for all your help. This helps. I will try these suggestions on my next quilt. I am still new to all of this. 8-)