Customer service nightmare

After many orders and cancellations on new and outlet XPS m1330s, I finally settled on a refurb one with a 64gb ssd yesterday with the 15% off xps outlet laptop coupon. I wanted to use my DPA with a no interest until 2009 promo, but their order system over the phone(only way to use DPA) was down for a while. I couldn't keep the laptop in my cart forever so I put in on my visa, hoping to get it switched today.
I called dell today and they tell me that I cannot just switch payment methods. The laptop has already been shipped. I can only accept delivery, return it, then hopefully be able to rebuy the rare config with 64gb ssd with me DPA. Btw, this would cause me to lose my 15% off coupon(expired yesterday).
Surprisingly, I found a similar config, same price before coupon but with an LED instead of LCD display, 2gb instead of 3gb. Not bad. I asked to see if I could still get 15% discount applied to this when I chatted with the online sales, phones closed now. They said only customer service can do this.
Meanwhile, I've been trying to get thru using dell chat. The few times I actually got into the queue, the session ended before it even started. Now, "All chat representatives are currently busy assisting other customers." for the past few hours.
I'm really thinking hard about buying a lenovo x61s instead now. Dell is pissing me off.