Was robbed at Knife Point what to do now?

I was meeting up with a friend I havnt seen in years. He set me up and took me to an alley way where I was robbed at knifepoint. They stole my phone, money, hat and jacket. I told the cops and they took the my friend into custody and are looking for the other 4. One of there friends contacted my friend and said if I call the cops off they will give everything back. What should I do? What if I call the cops off and they try and get revenge or if I don't I get there friends looking for me.

Added (1). They took my iPhone 6 plus(forced me to logout of ICloud), 70$, My Snapback and my jacket.

How to take off my iphone 6 plus case?

It's a really hard case and i'm so scared to take it off my 6 plus. There's also a scratch on it which is probably from the last i took it off myself. Isn't there any trick pr something?

Lock iPhone apps without jailbreak?

I have an iPhone 5c and iOS 9. Is there any way to lock WhatsApp and photos without jailbreaking the phone? I really don't want my friends looking at my stuff.

My iPhone 6+ is lagging like crazy?

I've had it for 6 months now and it's lagging a lot. Most my applications aren't working (they randomly freeze or turn off). The phone freezes a lot. The camera stopped working yesterday. Also yesterday (for like 6 hours) the settings 'app' would not open. It would either open up and just freeze or open up and it would be blank white, then it just randomly started working. Also sometimes when people try to call me it would either close before I could even answer, sometimes I'd answer and be able to hear them for a few seconds then it would close, or I wouldn't receive the call. And if that's happening I would try to call the person back but it wouldn't call. When I would try to use snapchat it would open up, I'd take the pictures then it just freezes. Instagram would open up, the pictures on my feed would start loading but then it also freezes. I tried rebooting, switching off my phone and resetting the settings a million times but it won't work. I also tried making more space by deleting things but that didn't help either
So if anyone knows what to do I'd appreciate that a lot because it's driving me mad

Will I lose everything if I update to iOS9?

My iPhone 5s is jailbroken and I'm still at iOS 8.1.2. I want the new emojis so badly and I'm willing to lose my jailbreak to update to iOS 9, but will I lose everything I've saved (such as photos, messages, apps, music, etc.) since I've jailbroken my phone (in January 2014)? Or will I just simply lose the jailbreak and still have everything else?
I remember I've restored my phone before to try to remove the jailbreak, but it ended up deleting everything I've saved since I jailbroke it and the jailbreak was still there.