White Samsung Galaxy S3 - Wanting To Swap For An iPhone 4S !

I have a white samsung galaxy s3 which is only a month old so in perfect condition. It comes boxed with all accessories that came with it. It also comes with a few cases. Its on Vodafone. I am looking to swap for a iphone 4s - either 16gb or 32gb. It must be on vodafone, boxed and in perfect condition. Please text if interested - no calls thank you. I work so will reply as and when I can.