How crazy and terrible! I agree with Dragonfly, keep the package as a reminder of how they rejected her and you. They WILL come crawling back some day...even if it's 5 years from now, someday they will want to be involved.
Even if you've grown emotionlly in the future and are willing to forgive (when that day comes), I hope you bring out that envelope and remind them...and make it HARD for them to get back into your lives. Don't accept their excuses and make them regret it.