Do you really think they should be able to get access to your account on 000webhost without you giving them the details? That would be scary...
"How do you know you are who you say you are?"
"You called me"
So make a backup your site, change the password to foobob, and give them the account info. Proceed to change the password on your hosting24 account after it's done.
Else, move it yourself.