The phone is WAY too big for my liking. I've tried to get to used to it but I just can't. You can't use it one handed anymore and the deal breaker for me is that it doesn't fit in my work trousers pocket.
The regular iPhone 6 is much more practical and just the right size, not too big but still bigger than the 5S.
The only way to arrange a return is by calling 191.
I’m sorry that you’ve had to wait so long to get through. If you try early in the morning at 8am or earlier in the day, you should be able to get through quicker.