How Do I Change Thenumber Of Rings On My Cell To Go To Voicemail How Do I Change The Size Of The Font In Received Messages On My Samsung GT-S6700T?

How do I change the size of the font in received messages on my Samsung GT-S6700T? - how do i change thenumber of rings on my cell to go to voicemail

I bought a Samsung phone S6700T GT in December of last year, had had no problems with it until a few weeks. The problem is that the font size of my messages ridicule from very small changes in received great, and I have no idea how to change it. There is nothing in the manual or the troubleshooting and I could not find everywhere. Any help would be very grateful.