Terrible first time customer experience

I purchased a XPS 13 through Dell Outlet via chat a couple of nights ago. The agent told me it would come with a free mouse that's a "$35 value!". I think that seems like a good deal and accept. After everything is processed I check my bank account and see a pending charge for the laptop and a separate one for the mouse.

I chatted and called with 3 different agents and was told it " had to be done this way for Dell systems, but once it ships the mouse's charge will fall off".

Fast forward to today . The laptop ships and I was charged for the mouse and the laptop. I call Dell support AGAIN and was told that they can't do anything about it. After some arguing he says he can discount my laptop to a maximum of $30 (which isn't enough to cover the $37 mouse charge). After I explain how none of this makes sense he says he can "make an exception for me" and request a refund.

How is it an exception to get a refund for something I didn't order? Also, how is it ok for not one but 3+ reps to lie to me? This is the worst purchasing experience I've had in quite some time.