Well, I had a look at the ILF Mobileapps website and I find a few things disconcerting. First let's address your problem.
If they claim the phone is offline and your sure that your daughter's phone does have a data connection, then it's possible that the app doesn't have the right permissions, in which case you'll need to have the phone in your hand to check. If you can get a hold of it, then got to settings>apps, tap on the ILF app and then tap on permissions. See if access any permissions to connect to networks is turned off. If the app is masquerading as something else so your daughter can't find it, then you'll need to know what that is. But, be careful. Enabling too much will compromise your daughter's security and privacy, especially from a company with a less than stellar reputation.
First, they are a supposed security company, but their website isn't secure? Too cheap to buy a certificate? Too incompetent on how to implement it? Too sneaky as to reveal who they really are (a certificate would have to be identified with a legitimate company to be trusted ... and the last thing they want is a trust warning on their website)
Second, their apps aren't on the play store. Why? Could be that they tried and were tossed for their practices, or it could be that what they provide is not what they claim it to be. I would also point out by enabling 'other sources' gives companies like this a 'back door' into the device to install other, more malicious apps. Now, mind you, I'm not accusing ILF Mobileapps of anything shady as I have no experience with the company at all, it's just that certain things don't add up.
I feel I should also point out that depending on your local laws, installing this type of app on somebody's phone without their knowledge or permission can be considered illegal wiretapping, even if the person is your underage daughter. You might want to check that.