So EE...
EE charged me an early upgrade fee (£320) but didn't take the payment for the 6s Plus, they simply charged me £6.98 for delivery and were supposed to charge me £109 for the handset but never did. My new bill has been produced and theres no sign of a handset charge applied, the early upgrade fee has been taken but my minimum contract term has not been extended thus my contract still expires in Sept 2016 instead of 2017.
Last year, they charged me an early upgrade fee, handset charge and extended my contract correctly however, they applied the early upgrade charge back to my bill as a credit but never took the early upgrade charge from my bill. I ended up with a £300 credit on my account for 3 months until I requested it to be refunded, which they did!
So, all in all, I sold my 6 Plus for £400 meaning i'm £80 up and have the 6s Plus 64GB at £35PM for 10GB data and fully unlit text/mins inc 0845/0870 numbers.
Not a bad little deal.
In addition, my Apple Care+ on from my 6 Plus is being transferred to my new 6s Plus for free and doesn't expire until 04 August 2017