Angry and unsatisfied

I am very disappointed with Truworths online and customer service with their recent service toward me, after so many email i sent them requesting them to cancel my online order that i placed on the 11th June then i cancelled it on the 12June at 12:51 it was not even 24 hours requesting them to cancel it and they told me they can't cancel the order that has been processed, the order was still in their premises it was not yet ben dispatched but they refused after so many emails i have sent them, i once order a dress online in the evening but to my suprise the following day the order was cancelled with no reason or explanation and i was refunded that order was also processed.

My question to them what was so difficult for them to do the same with this one upon my request, regardless of many emails i had sent them they went ahead and courier it, there was another order i made online with office London in December it was also processed but again it was cancelled and i was refunded, but why this particular item, i told them they mustn't go ahead with it because my installment will be charged based on the balance that will include this transaction but they did it,

I won't go to the store to pick up that order and do the return at the store as they told me to do so, they must see what to do with it as i just received an sms that my order has arrived at the store ready to picked up by me. They have all my details on their system. And i want them review my installment and my balance. Thank you