Unfortunately rolling an account back would require rolling the entire forums back in a situation like this and would result in further losses since the PM issue (posts would be lost, so forth). I have checked the database backend and the data for the PMs are still there.. this is puzzling why the forum software has been effected in this manner in regards to a single accont.
I have run several forum software maintenence scripts to check for errors in the database, none were found during the run process..
I have sent you a PM to test the PM system in regards to your account.
If it comes down to it, what I shall do is export what the database backend has and provide that data to you, this way at least you'll have the PMs themselves.