Mobile SMS verification upon withdrawal. Even if the users chooses to skip mobile verification upon signing up, they must confirm their mobile number before their first withdrawal.
Secondly, The payment links are forwarded to the user's email which they can use to claim their earnings on Lobstr. We've partnered up with Lobstr.co to prevent any this issue with duplicate accounts (emails, sms verification etc).
We're using Twilio for sms verification which pretty much limits all blacklisted mobile numbers. This would prevent any user to use SMS verification services that allow you to register hundreds of accounts. That being said, there are always ways to somehow do it but it just have to be such a costly and time-consuming method that no-one would actually bother to. Its more cost-efficient to just buy the pro-membership package for $10
I have to say out front that I'm not familiar with Lobstr, so I didn't know how it works (I barely roam around XLM), but I assume (from a brief visit to their site) they're a wallet provider? If I am correct, does it means the one and only withdrawal method is to that platform? Or would the users be able to withdraw to whichever xlm address they want to?