Dissatisfied customer

So on the 12/03/19 my fiancé ordered me a knit from your online department for me, she selected the express option as we were scared there would be no sizes available as instore this knit in my size was sold through. It was due to arrive the 15/03/19 give or take with express... So that means it was suppose to arrive the Friday. She only received a message on the 19th to say that it's ready for collection? So why was she charged for the express fee? To make matters worse when we collected the knit from your V&A branch last night it was a size Small instead of a XL??? The sales assistant was very disinterested and I swopped it for another knit instore. Why was she charged the express fee if it wasnt delivered on time? How was it that the size received was the incorrect one? We are deeply dissapointed at this level of service and would really like someone to shed some light over this matter and it to be dealt with urgency!