Why doesn't my iPhone 4S update to the new software?

[iMore Question]

My phone's internet has been weird for a couple of weeks now. For example, the internet will ONLY work in the kitchen in my house and outside. On some days It will work perfectly fine but other days it doesn't work, so I thought I should try updating my phone to the newest software. However, whenever I try to update my phone it keeps failing. I've already tried updating it through iTunes and it didn't work there as well. I've looked online for solutions but so far nothing's worked.