Password problem

Hello,
i've received and e-mail telling me that someone might have been accessing my e-mail acount. so i decided to change my password. i've changed to a 18 characters password. the thing is, when i was changing my password they let me put a 18 characters pass, but now, when i try to login they only accept 16 characters. then i tried the password recover question but for some reason my answer (wich i know it is correct) isn't accepted. i have downloaded some programs to recover passwords but they can only work when it (password) was stored in the computer. i really need help, i've the most important business in my e-mail acount and i can't afford loosing them