ok, first no forensics would get it back for you, as it was never on your computer to begin with, it was only on the mail server, so that sounds suspicious what they are offering you as it would never work.
If you have searched in Gmail and checked the Trash for it there, then the only chance you have is to request that google check the server for it and return it to your inbox.
If it was only a few days it would be very likely you get it back, but being 2 months, I will not mislead you but the chances are slim, but it is worth filling in.
The form you can access here
Fill in the form and allow 48 hours and if the email can be recovered, you will be notified and the email will be returned to your inbox.
But in this situation, this is the only option you have.
If you would like any additional information or assistance, please do not hesitate to let me know.
And if you can take a second to rate my service by clicking one of the stars at the top of the screen then submit, that would be greatly appreciated.