innerfence: why does it say the infinite sms is not available?

It's no longer available since Google decided to shut it down abruptly. You won't be able to get the app now and indefinitely (see below, it's a reply I sent to someone else regarding why Google shutdown the service)

Remember that super long T.O.S. (Terms of Service) that you had with Google when you signed up for your gmail account? Don't remember? You may want to take another look at it...

Go here--> http://www.google.com/accounts/TOS?hl=en

"13.3 Google may at any time, terminate its legal agreement with you if:...(D) Google is transitioning to no longer providing the Services to users in the country in which you are resident or from which you use the service; or

(E) the provision of the Services to you by Google is, in Google’s opinion, no longer commercially viable.
...

13.4 Nothing in this Section shall affect Google’s rights regarding provision of Services under Section 4 of the Terms.

13.5 When these Terms come to an end, all of the legal rights, obligations and liabilities that you and Google have benefited from, been subject to (or which have accrued over time whilst the Terms have been in force) or which are expressed to continue indefinitely, shall be unaffected by this cessation, and the provisions of paragraph 20.7 shall continue to apply to such rights, obligations and liabilities indefinitely."

In plain English, it means that Google can do whatever it wants, whenever it wants. They never said that they guaranteed their services, now did they? All T.O.S.es are similar to this one and they won't change anytime soon...