What was the profile of the seller on Localbitcoins ? Does the name matched on the profile and in the Revolut operation ?
This may very well have happened if the bank account access and details they used were hacked/stolen.
And this also would be a reason for Revolut to close an account.
If there was any claim regarding a particular transaction, they better shut down the account instead of investigating further as their aim is to become "the Amazon of banking".