Help downloading a PC Game!?

I DO NOT WANT TO GET THIS FOR FREE! I have bought Sims 3 ambitions, I have sims 3 already but that isn't the point the disk is damaged and won't download I have lost the receipt. I want to download it online. What site should i go to I have the serial code to enter (Unused) I really need this but just to tell those hackers. I don't want anything hacked I just want to download the game and enter the serial code! NO KEY-GENS!