Using Wi-Fi on iphone's (vodafone)?

I have got a new iphone and I'm on a contract with 500mb of internet, I'm with vodafone and I was wondering wether using the internet while connected to Wi-Fi (my home Wi-Fi not a hotspot) instead of mobile data uses up my data allowance?

How to retrieve deleted voicemails from iPhone?

I have an iPhone 4. I have never backed it up nor did an update (I know ridiculous). I recently received a new SIM card because my old one was "accidentally" deactivated. Upon inserting my new SIM card, I lost all my voicemails. I had ones saved from my dad who recently passed away. As you can about imagine it was devistating. I had been meaning to save them but hadn't gotten around to it and obviously didn't plan this happening. Is there ANY way possible to get these voicemails back? I spent hours on the phone with AT&T and they couldn't help me. I don't understand how they can just be gone all of a sudden. I know it's part my fault for not backing them up. Any help would be more than appreciated!

Update apps without updating ios?

I have a jailbroken iPhone 3GS with IOS 4.1 so can't update the software to IOS 6.0 in iTunes, else the phone is permanently locked. I want to download some apps including whatsapp but they keep telling me that they require IOS 4.3 or higher. How do I go about installing these apps, especially whatsapp?
any cydia tweak or something?

My Instagram keeps crashing? - 1

So basically my Instagram keeps crashing by exiting the app every time I go to follow someone that I've accidentally unfollowed and it does this every single time I try to follow them back. I have the iPhone 4S and I've tried logging in and out, turning my phone off and on again, and even re-installing the app but none of it has worked!
Does anyone know what could be the problem or even how to fix it?

Thank you to anyone who answers.

Added (1). Actually, it does this whenever I go to follow anyone! So I can't follow people anymore… :/

How to use an unlocked iphone 5 from any US carrier in india?

I live in india i'm planning to purchase an iphone 5 but i was thinking that what if i buy a locked iphone from US and then get it unlocked as a locked phone would cost around 199$ and unlocked is 549$
so i wanted to know that is it possible? And what is the process of unlocking it? Does it requires any documents to buy a locked phone?