IPhone 4s stuck on searching after screen replacement?

So i replaced my moms phone screen last night, and everything was working fine but a minute later the signal went to "Searching". The Wi-Fi still works just no cellular. I factory reseted her iphone cause people said that would help but now it won't activate cause its still on searching.

My verizon iPhone 5s is still working?

What I mean by it is, ok so I already switched my service to a lg G3. But the data is still working on the iPhone, the data works on my lg G3 too, but the iPhone seems to still have service? Help or is it a glitch? If I use it will verizon know?

How to change the apple ID in Apps Store after i change it in my Settings?

I changed my apple id because my previous email address is no longer existing, now whenever i try to update my apps in App Store, it still shows my old apple id and asking for the password of it; apparently i have a wrong apple id because that is not my current one. I tried to log out and log-in just to see if this will work but nothing changes. Now, i have lots of apps to upgrade and i can't, i have an iphone 4 updated to iOS 7.1.2.

How does a company afford giving lifetime warranty?

Tech Armor makes high quality screen protectors that came with scrap card, dust removing stickers, and microfiber cloth along with the screen protectors (3pk). All that only costed me around $10. I've had my iPhone with their SPs since August 2013. Right now they are giving me my second replacement pack that includes all the extra items because of installation issues and scratches on the installed one. I'm just surprised that they can freely give replacements. Are their profit margins really high or something?

Can I trade In my IPhone at T-Mobile?

So I have T-Mobile and I've been with them for about 5 months with no contract. I have an iPhone 5c and I'm paying it off they say as long as the phone is paid I can stop paying my line with no problems and it will automatically disconnect. My bill has been pretty high so can I trade in my iPhone for a cheaper phone, And the remaining balance for the iPhone will pay for the cheaper phone? That way I can have a paid off phone and just switch company