I just found out, that some signatures will not count!! So please check the following (answer from change.org):
Please have those who you believe have signed the petition contact us if they are having an issue with the petition accepting their signatures. We will gladly help them. Until we hear from them, we do not know why their signatures were not accepted.
In order to sign a petition successfully, your supporters would have to make sure that they have the following three requirements:
1. A compatible browser that is in it's current version. We do not support beta or older versions of Firefox, Google Chrome, Safari, or Internet Explorer.
3. A valid email address that hasn't been used before to sign the petition. One email address/signature.
Please tell this your friends, if they were not able to sign!! Thank you!!