novelty or nonobviousness of your text message/valet system. But few applications fly through the patent process, so if a patent has not been granted (and we're not referring to provisional patent applications), we'd suggest that you search the USPTO website to determine where, in the patent food chain, the patent is currently located and to verify that you are not listed as a co-inventor. You need to also assess accurately what your contribution was. The more specific and detailed your contribution the stronger your position. But if all you provided was the one-sentence idea as in the question, above, the weaker your claim to invention co-ownership.
Can you afford the fight? Assuming you have a strong claim, you're going to need a patent attorney in order to validate your claim to co-ownership. (You'll need a patent attorney because you will need someone familiar with the the patent process and with claims such as patent fraud.) It's possible (though not likely), that if you have a really strong financial claim, you can find an attorney who will work on contingency. Before you proceed, consider the financial outcome. You don't want to spend more money on lawyers than you'll earn from your patent.