How to prevent someone from using our Wi-Fi?

My brother bought an iPhone from our neighbor. I was setting it up and it asked to connect to a Wi-Fi service and so on. So when I was almost done setting it up, it said that the person before had there account still attached to the iPhone. So my brother went to ask him if he can remove his account and he said that someone owned it before him and he didn't know how to contact him etc. So when I found out, I turned the iPhone off hoping the Wi-Fi won't be connected to our Wi-Fi but it still was. Then the next day my brother returned the iPhone but it was still connected. What can I do to remove the device from using our Wi-Fi? (Sorry it's long and if it doesn't make sense IIm sorry)

How to reset an unlocked at&t iPhone 5?

So I have an iPhone 5 that was my older siblings. He had it on at&t contract and it's done. I've unlocked it via an outside source (not AT&T) but in USA. But how do I reset the phone(I.e I don't want his apple ID. I want to make my own. Delete all his apps and download my own) basically make the phone brand new "software wise"? I've always used android phones hence i'm clueless when it comes to iphones. I would appreciate the help!
Also IIm not a electronic geek so try and explain it as simply as possible. I d appreciate that.

Skype versions different? Can't connect to a call?

So i have an ipod touch (VERY OLD AND I DIDN't UPDATE IT TO IOS6/7 OR WHATEVER) and i downloaded skype to have a call with my boyfriend, but he uses skype from his iphone 6.

is it because its different versions?

there's no way to fix that, huh?

- Thanks!

How to get my Iphone pictures back on my laptop?

I had a dropbox account and my pictures started to go on there but I deleted my dropbox account and now my pictures won't go back on my laptop but thats where i want them how do i get them to just load straight to my laptop again?!

IPhone 6s otterbox defender case issue?

Okay so I just got a rose gold iphone 6s and don't get me wrong I'm very happy and thankful! It's just that I get that since I broke my old iPhone my parents got me an otterbox but when I put the otterbox on, its SUPER hard to tap the screen like I have to tap really hard but when I take it off its so easy. Is something wrong with my otterbox or do I just have to live with it.

Added (1). P.S. My dad won't like it if I take any part of it off and I get why and I respect that so I can't do that either.

Can I jailbreak my iPhone if it has an older version of iOS?

My iPhone has version 8.4 and I want to jailbreak, but when I downloaded the 8.4 jailbreak and tried installing it on my iPhone it wouldn't work because it just prompted me to download the jailbreak for 9.0. I can't update to 9.0 because the latest version is 9.2, and there's no jailbreak for 9.2 yet. Is there a way to jailbreak my phone that has iOS 8.4 or do I have to wait for the 9.2 jailbreak to be released?

Should I put a case on my iPhone 6s?

I just got an iPhone 6s not to long ago and I was wondering if I should cover up its great design with a case, or take the risk of dropping it?