From what I have read seen on different  forums and the alike...when it comes to multi accounting,  75% of the time these casino's are never wrong to flag accounts based on multi accounting as they have the flagging techniques in place to find such users because this is their business to stop any possible promo abuse and the alike...
FYI use of a VPN can get your account flagged as IPs show up on other accounts hence this hurdle..but if nothing in these lines was committed then I trust Rollbit will sort this out asap! Good luck.