I also met the same iusse,I mistakenly deleted some important text message from my galaxy s3, some people said it was imporssible to recover them, but some people also said there is some app can recover, I was confused,p lease help. I just test Vibosoft data recovery for Android program, that's very easy to use and powerful, all of my lost sms were recovered, It was worh a recommendation, this is the article:
how can I restore deleted message on Samsung galaxy s2/s3/s4 device