Cancel Order

I have desperately been trying to cancel an order I made with Dell 10 days ago that has been delayed by 2 weeks. I placed the order on 7/6 with an initial delivery date of 7/9. Late night on 7/8, I get an email saying that the order is delayed and will be shipped on 7/22 and delivered on 7/24. It also gave me an option to cancel the order if I not longer wanted it. I selected the option to cancel as I will not be available to receive the order for a month and the only reason I placed the order was because of the quick delivery date. The cancelation was rejected and I've been contacting support every single day since 7/9, until today, 7/16 and no one is able to help me confirm the cancelation. The order is still 6 days away from shipment, and the product also now shows up as "Out of Stock" on Dell's website as of today. How hard is it for this order to be canceled? I will be disputing this with my credit card if this issue is not resolved before the order ships out.