Spree cannot deliver the correct order

I bought a pair of shoes from spree online size 5, when the order was delivered the size was incorrect a size 4 and a size 5 in one pair, I then called to get my order exchanged which was collected by a courier company and spree was supposed to return my order with the correct size but they did not, I waited 2 weeks and the called them again which I was told the no longer have a size 5 in the colour I ordered so I asked for them to give me a different colour of that pair a size 5, I was told my order will be delivered in 3 days only for it to be delivered with the an incorrect size again a size 8, I am very disappointed with spree it's now been a month i'm battling with spree.