Edit your title please. It should be 1xbit. (You are talking about 1xbit. Right?)
1xBit.com's already been red tagged due to previous issues but I suggest you also give them a feedback yourself then reference this thread so
users would know about the multiple issues.
I must say that I don't approve of this practice of requiring customers to send documents by post.
They usually start off with asking for multiple documents, selfie + ID's, records and such. When the customer manage to comply with it, they then further ask for more.
Ultimately demanding for physical documents by post?

@OP, what was the reason given for the suspension/freezing of your account? Why did they even hold all withdrawals in the first place?
