|Sorry, but unless you can recover your emails from the old drive I expect they are lost.|
If old emails are important you must maintain your own backups of them. Hard drives fail and data can be lost for a variety of other reasons as well. You must be prepared when (not if) this happens. This is your responsibility, not your email provider's.
If your email provider maintained long term storage of email for everyone it would multiply storage requirements. This would raise costs which would have to be passed on to subscribers. And all for a service that few subscribers would want.