Facebook won't download on my iPhone 4S?

I recently got my iPhone back. The screen cracked so I had to get a new phone. But a few weeks ago, I got the screen fixed and I got service on it. It has been acting up ever since I got it turned on. It constantly says invalid SIM card, then I have to keep restarting it. And yesterday, I would try to go on Facebook, and it would just keep taking me back to the home screen. So I deleted it. But now today, I keep trying to download it and it won't load.
10 points for whoever can help.

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