You have to be at least 15 years old to use Kik Contacts. If you're between 15 and 18 years old you need permission from a parent or legal guardian before you submit your Kik username and start using Kik Contacts.
If you break the rules on Kik Contacts you will be permanently banned from using the service.
You can deactivate your account by unchecking the "My profile is visible"-checkbox on your profile page. When you do, no one will see you on the site until you check the checkbox again.
No, you are not. To prevent fake users you are only able to register one (1) account.
Nothing at all! It's 100% free to use the service.