They seem to be a reseller or something.
On this webpage from AEI's site, @contact.net is mentionend.
The AEI Internet Subscriber (email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org) is the account, registered for Internet Services (DialUp, HighSpeed). This account may have the AEI Voice Subscriber sub-accounts. Logging on as AEI Internet Subscriberyou can manage all sub-accounts.