App doesn't work – DUO Free Secure Messaging: Text Now via Encryption Review

I paid for app on September 30th but I still can't log in. One star is more than I would rate but there is no option for less. It is almost 3 months now and chances of getting a hold of customer service are like getting a jack pot on lottery.
Review by Evaan77 on DUO Free Secure Messaging: Text Now via Encryption.