Think iv been scammed what do I do?

Ok I bought an iphone from gumtree and I paid through PayPal, they sent me a different phone a really cheap one so if I claim in PayPal they still have proof if postage so is there anything I can do?

My iphone 5 is sometimes slow and sometimes fast?

My iphone 5 is sometimes slow and sometimes fast?
sometimes when i'm using LTE on my iphone 5, my iphone 5 would slow down all of the sudden but then when i turn it off for a day its really fast. This happened at my house where i have been using my iphone for a long time and its fast there. This issue happens alot, its not my first time for this. I seriously need help
is there something wrong with my iphone? Is there like a virus? I'm scared.

My iphone 5 is sometimes slow and sometimes fast? - 1

Sometimes when i'm using LTE my iphone 5 would slow down all of the sudden but then when i turn it off for a day its really fast. Is there something wrong with my iphone?

Added (1). How do you close your running apps in the app switcher?

Opera mini won't work on my iPhone 4

Tried to install opera mini. When it initially started it displayed the menu bar then the menu bar disappeared and a white blank page remained with the spinning icon showing it was updating something yet after 5 minutes nothing appeared. I tried to close the app and open it again but nothing worked

DSiSim keeps crashing when opening?

I've downloaded DSiSim on my iphone 3gs, but each time i open it it crashes. I've tried everything to fix this problem but none of them worked.

Is It Possible To Get Siri On IPhone 4?

Is It Possible To Get Siri Working On IPhone 4 with ios 6.1.2 With The Evasi0n Jailbreak. I've tried looking on YouTube and nothing has worked for me, Siri either doesn't enable or crashes every time. And yes I have the latest Evasi0n update.

Is there another way to reset Iphone 4?

I wanted to reset all my settings so I did and now it's a black screen with a loading sign (circle) and it's been like that for a few hours, I tried holding the button on the top and nothing happened. I tried connecting it to my macbook pro and that doesn't work either. What do I do? Do I just wait for it the battery to die or get a new iPhone?