They probably can't just refund it because the deposit & withdrawal might be an attempt of money laundering by the user.
According to OP, the user said as soon as he/she sent the deposit the account got locked.
So it is too early to state that it was a money laundering attempt (deposit & withdraw). But so far it looks like a geo-restriction issue as said by Yahoo.
Cloudbet needs to join here to tell their part of the story. Does anyone inform them about this accusation?