IPhone 4 problems with texts?

I have an iphone 4 my dad has an iphone4 and just recently my brother got an iPhone 4S but his is on a different plan than ours. Ever since then my dads phone has been receiving all our texts sent to other iPhones he doesn't get it if its a regular message only the iMessages. I asked him about it and he has no idea why. If anybody knows what the problem is please help.

Reboot your iphone by pressing down on the upper right button and turn it back on. Also make sure you download all updated software since its free because many times apple updates these glitches in new software s.

You're getting that messages because one of you share an Apple I. D you need to have separate Apple I. D's to be able to receive your own iMessages without them going on to each other's iPhones.

Go to
https://appleid.apple.com/...lang=en_US

and fill out the form and then you'll have your own Apple ID and be able to get all of your own messages without them being transferred onto your dad's iPhone.