Hello there cyber world,

I have a bought a brand new Verizon operated iPhone 4. Now I'm facing several problems which I try to solve step by step... ok so here we go:

The phone was send to somebody as a replacement phone so it's still in plastic with the serial number sticker on it which is completely untouched. When I turn on the phone and go through the steps of activating it, it tells me that I'm not able too do so. I get the following:

"Your iPhone could not be activated because the activation server is temporarily unavailable. Try connecting your iPhone to iTunes to activate it, or try again in a couple of minutes. If this problem persists, contact Apple Support at apple.com/support."

Ok, so I don't have a Verizon sim card in it but it does connect to my wifi at home. I do know that it runs 5.0.1 (says it on sticker on back). I also know that I need to know the firmware it's running to deter if I will be able to unlock (for Tmobile) after jailbreaking, correct? Will I need a Verizon sim card to find out what firmware it is running since I can't get to the point where I have access to settings-general-about...?

Please somebody help me out. I have researched the issue but wasn't able to find a straight simple answer to it (if that's even possible . Also to whoever is willing to help, please use "simple" terms/words.
I'm German and some terms/words I unfortunately can't look up in the dictionary which sucks...but hey, I'm trying my best here. Promise!
Thanks in advance