World of Warcraft mailbox memory (keystroke)?

My account was broken into and all my gold was stolen and items sold or destroyed. After going into my mail box I began to push each key on the send mail tab. After typing the first letter most letters pulled up nothing, however a few pulled up a few unfamiliar names. I don't know these people. My question is...does anyone know if the names that pull up in the send mail tab when u begin to type someone you have sent mail to in the past. I can't explain a couple random names pulling up unless tha is the case. Please help if you know for sure. Thanks in advance.