IPhone 4S not sending SMS to one contact?

Me and my friend both have the iPhone 4S and we're on the same provider. I can receive all of her texts and I can send her iMessages, but when I try to send her a text, it doesn't send. I have tried deleting her and resetting it, i turned off my phone, I have the 10 digit number, there's seriously nothing I can do! (We're with Rogers by the way)

How to block someone's calls and texts from my iPhone?

So my ex boyfriend won't stop calling and texting me and it's really pissing me off. I've been ignoring his texts and calls for the past 2 weeks but he still doesn't seem to get the hint. I don't claim to be the most tech savvy person in the world, so any clear, easy to understand, step-by-step procedure on how to block a number on my iPhone would be greatly appreciated.

How to download an app without getting the newest version of it?

I currently own an ipod and i have the normal instgram app. Instgram updated, and my friend got the update and showed me, and i absolutly hate it. You can't ajust photos before uploading and it makes you crop even more of your photo out. I really like the one i currently have, and i do not want to update. BUT i'm getting an iphone 5 in 3 days and i know when i come to download instgram it'll give me the newest version. Which i do not want. Is there a way i can download the app to my iphone 5 without getting the latest verson of it?

How to authorize my Toshiba Satellite?

My computer won't let me use my iTunes because it says I need to authorize my computer. It's a Toshiba Satellite C875D - S7330. Does anyone know hoe to authorize it or at least transfer my iPhone music to my iTunes?

How would you describe an iPhone?

- to someone who has never seen one before, how would you describe the outward appearance of an iPhone e.g. The shape, size, colour etc.

How to get a notification when my iPad is found through Find my iPhone?

My house got robbed today and my iPad got stolen, since my iPad does not have 3g I won't be able to locate it directly, but once they connect to the internet I will. I wan't to leave Find my iPhone running at night (on my laptop) so that I can track it when I'm asleep, is there a possibility to give me a sound notification so that I will wake up once it's been located? As in, they connect it to their Wi-Fi.