The problem is that i need to know how to show them scriptually that their in a false religion
If they really believe they are in the true religion then it can't be done. You're wasting your breath. Because they're not going to listen to anything you have to say. They already know the truth (so they think).
If you want to expose the WTS/JWs, you'll have to do it slyly and discreetly. Just drop tidbits of info, hints of things. Get their curiousity up. Let them start to wonder, doubt, question. Nothing you say directly is going to make them say, "Ya know, he's right. JWs ARE a cult!". Ain't gonna happen. They have to have a doubt. They have to wonder if maybe something isn't right. Until then, as long as they think they're right, anything you say is apostate reasoning and they'll cover their ears and go, "LALALALALALA".
At the risk of sounding like LeavingWT, I would recommend that you read "Combatting Cult Mind Control" by Steve Hassan. You can learn how to get them to think for themselves instead of a direct confrontation with them.