I would suggest trying harder to get in touch with those free signups. Write them personal mails, not newsletter/ survey sounding mass mail. Pick 10 of them, te

I would suggest trying harder to get in touch with those free signups. Write them personal mails, not newsletter/ survey sounding mass mail. Pick 10 of them, tell them you are the founder, tell them why you started it and need there help finetuning the product, that you don't want to sell them anything but offer them $20 for a short Skype etc.