Iphone 4 no service. Switched from AT&T to Tmobile?

My brother gave me a gift… An iphone 4.
He jailbroke it a long time ago because it use to be his.
Now I tried to switch from his service AT&T, which he isn't a part of now (because of jailbreak)
to Tmobile with a Sims card and activation kit at Walmart (50 bucks including the sim and activationness and 30 dollar montlhly.
So I got all that set up and my iphone still won't work!
Now what?

Why can't I get pretty little liars messages?

Okay so I have T-mobile iPhone and I'm trying to sign up for pretty little liars text messages but when I text PLL to 462223 it says that message blocking is active. I can text other people but not this number. Why? And how can I disable it

Just found an Iphone 4s, should i keep it or sell it?

I was cleaning my truck and found it. I let it charge for a bit turned it on and found out it belongs to a relative.

I'm leaning towards returning it to them but the calls/messages are over a month old so they may a have a new one by now.

But the little devil on my shoulder is also telling me to keep it instead. It's way better than my current phone(pre paid).

Lol if it didn't belong to someone i know i would keep without a doubt. But yeah.

Added (1). @ cucumber. You can add iphones to pre paid plans. Like straight talk, all you have to do is get a sim card.idiot.

@barbara. I do have a job.idiot.

Will my iPhone work with tMobile?

Okay so I haven't bought it yet but I found used iPhone 4 for a good deal and it says it is GMS, which is what I need, but it also says its for at&t but I was wondering if I coukld take it to the store and get a new micro simcard and just change phone but not mess with the plan at all. So basically I'm asking will the iPhone still work with tMobile and if it does will I be able to switch phones with ease in the same family plan we have. And also possibly keep the same phone number?

Getting rid of iPhone's other?

Most of my phone's usage is belongs to the "other" portion. I have an 8GB and the "other" takes up 4.76 GB. I haven't even updated my phones system. I deleted messages, mails, and got rid of any unnecessary things on my phone. Is there any other way to get rid of the other!

Just found an Iphone 4s, should i keep it or sell it? - 1

I was cleaning my truck and found it. I let it charge for a bit turned it on and found out it belongs to a relative.

I'm leaning towards returning it to them but the calls/messages are over a month old so they may a have a new one by now.

But the little devil on my shoulder is also telling me to keep it instead. It's way better than my current phone(pre paid).

Lol if it didn't belong to someone i know i would keep without a doubt. But yeah.

Should I settle for an iPhone 4 or save for a 4s?

I currently have an iPhone 3gs which is extremely slow and it just cracked. The camera also never wants to take pictures. It just crashes. I'm meeting my favorite singers on August 8th and I really want a phone by then for picture purposes. I currently have $230 which I could use for a 4 or risk trying to keep saving for a 4s. Is there a big difference between a 4 and a 4s that is worth trying to save for a little longer? Where could I get it for a bit cheaper than other places? How much do they cost at Entertainmart?