There's some mail changes on the way in Quantum Rise 1.0.1.

To address performance issues in EVE we are making some changes to the EVE Mail system in Quantum Rise 1.0.1. You will now be able to fetch up to 1000 undeleted EVE Mails, however, EVE Mail number 1001 and beyond will not be fetched, whether it has been read or not. To gain access to those EVE Mails, you must delete newer EVE mails. In addition to this all EVE Mails sent by NPCs that are older than 3 months will be deleted.