Lastly, you gave it that you're denied of making withdrawals because of being suspected of multi accounts, this may happen when you lest expected, maybe in the past, or you handover your device to some who already enrolled for the same platform, if you're accused, check on the possibility first before making your way out.
I think OP was very clear that he has only one account on Rollbit, and what are the chances that someone else used OP's device, the chances are quite non-existent. This is not the first time Rollbit are asking people to list the accounts they have on their platform, i find their approach somewhat weird, but it is what it is.
OP do keep us updated if you get a reply from Rollbit's compliance team, though it could be frustrating, but you have to exercise some patience.