I was screwed by Sprint as well. I have been venting over at the Northwest board. I argued the point by email and received the same reply as you.... You got miles in May 2000 so you don't get any now.... I said that was not on my agreement that I printed out and that they were charging me under the terms I signed up for. We went back and forth 3 times and luckily I received a $90 check in the mail to switch back to ATT who I had left for Sprint to get me back, I switched.
Then wouldn't you know it, I received an email from Sprint wanting to know how I liked their customer service!!! I cannot reprint what I wrote in a public forum!!
They owe us all 40K in miles just for the aggravation...