Iphone app that is like kik?

I got a message saying that kik is gonna start charging if you're inactive, so i deleted my account.
The problem is other apps like whatsapp n viber require phone nos to communicate with people whereas you just needed to know the person's username in kik.
So are there apps like kik which do not require phone nos to communicate with people (except skype, facebook, twitter)

What's app? Viber? Tango? All really good apps except what's app charges.

I have kik too but I haven't received this message, I really doubt it's true as the main point of kik is that it's free. Also people used to say whatsapp would start charging if you're inactive but it's been half a year and they're still not charging so I don't think you need to worry. But if you really want other apps there are LiveProfile and Touch.