In either case, expending a few neural cycles prior to the action would be beneficial.

I'm all for being able to initiate billing inquiries online--in fact, I'm ditching Bank of America because I can't dispute charges on line.

But in Amazon's case, this isn't a dispute, rather this is asking them to forgive a (hopefully) one time transgression, which is much easier to do by speaking to someone, than filling out a form.

I find it similar to haggling for a temporary reprieve in my fantastically high cable bill.