Sally and Vera - you might want to try a different bean variety for freezing and see if that makes a difference. I've been freezing beans for years, and while I wouldn't say they're exactly the same as cooking fresh young beans, they definitely don't become fibrous or mushy.
I blanch the beans for 3-1/2 minutes in boiling water, cool them down quickly in ice water, spin in the salad spinner to remove excess water, and package in freezer baggies. To cook, I add the beans to a pot of cold water with a little salt, put the burner on high until the water starts to boil then turn it down to a simmer; just about 15 minutes total gives us tender-crisp beans - just past what I call the "squeaky stage" (where they kind of squeak when you bite into them).
