Text messages using iPhone 4S | Phone/Device Issues and Features | Consumer forum

Just found this on the official 7-11 website. Does this not mean if you DO NOT have the text Messaging plan you can still send text messages but that they will cost you $ 0.15 each outgoing text?????. If I have reason to send maybe 5 text messages a month at 15 cents per text it is still cheaper than a $ 15.00 plan!!!
That takes me back to my original question, WHY can I not send text messages?????:

From 7-11 website

Text
How many texts could you text if you had unlimited text?
With our $15 Unlimited Text Messaging Add-On, you can tip-tap-type as many outgoing text messages as you want, and since incoming text messages are always free, your speedy fingers will never need to stop.
Simply register for a SpeakOut account, make sure you have at least $17.00 top up funds, and click activate*. OMG 2 EZ!
Oh, and make sure you have sufficient funds for your phone number in your account before your add-on automatically renews. Don’t worry, we’ll text you two days before the renewal date, and again when it has been successfully renewed**. If it wasn’t successfully renewed, you can still text anyway. Just remember that without the add-on, you’ll be charged $0.10 per outgoing text message.

Our rates are changing effective May 15, 2015:

Outbound text message fees will increase from $0.10/sent message to $0.15/sent message. Incoming texts are still Free.