From e-rewards:
"We appreciate your feedback! We understand that the issue is quite frustrating on your end but as part of our account security, our system will not allow VOIP or Google numbers to be used for account verification. Sadly, there's currently no process to override this type of restriction aside from using a different number that is valid. We sincerely apologize for the inconvenience this may be causing you on your end."
I could appreciate this restriction if I were applying to participate, but to put this new restriction on after years of participation and a large points balance seems to me a breach of contract. Now I understand this isn't worth going to court over, but I can at least warn others of their attitude towards their users.