Your story and the story reported here are not the same. Your story has nothing to do with a warranty being voided. It has to do with whether it is economical to repair your machine. If you wanted to pay more than the cost of a new MacBook Pro to repair it, I am sure Apple would probably be glad to take your money. But the quote you provided tells the story: "It would cost more to repair than to buy a new one." They are saving you money.
Unless you are in romantic love with your old MacBook Pro, why would you pay more than the value of a new, faster, greater capacity Macbook pro to renovate an older, slower, lower capacity machine and wind up with a worn, scratched used machine? Sentiment is only worth so much. If I were Apple, I'd want your money up front before doing the work.
Buy a new machine, pull the drive out of yours and mount it in a cheap external case and retrieve your data.