Something like refusing work after taking money is generally unacceptable in any artist communities and if the info about that gets around, the artist usually gets expelled forever for being a scammer.
If you want a server where you can find somewhat reliable artists (or at least people with any sort of work ethic), here's one dedicated purely for commissions. You can ask if there's someone doing vtuber avatars there.
discord.com/invite/T828WNSThere's also waifu factory, which is somewhat okay
discord.com/invite/ktFCkEJ 
