You can use DOSSIER, an app to organize customer conversations in HubSpot. The free product logs emails for the last 30 days in HubSpot with company, contact and emails. Go to the company site http://www.dossier.work. To retroactively go back more than 30 days, ex. to 2 years, you have to be a paid user and fees are usually $25/mo for email volume that is on the low-to-medium scale.