Can someone please advise me what to do or are these lost forever?

These were important invoices which I kept a record of now nothing before december 2012 show? I do I recover these?

I have made sure all my email settings were correct so no files would be deleted and I have tried to recover deleted emails as this was suggested on another thread but without success.  I reguarly put entries into this folder so it was still active, can you please help me recover these files/emails?

Kind regards,

Steven