Information on why your document is not accepted is provided in the buying-flow itself, before finishing the transaction. If required, you can get assistance from the onramp you used for your transaction.
In rare cases, manual enhanced due diligence is done by a fiat onramp after you submit your payment, which can take a few minutes to a few hours. It could be the case that, based on this enhanced due diligence, additional information is requested. In such a case, you’ll be informed hereof by emali.Info on how to do this is found in the mail you received.