You likely never have to repurchase any Adobe product - and depending on which version it might not be available for purchase anyways.
You have not identified which Creative Suite, so here is a general link to lead you to the download for whichever version it might be...
Download and Installation Help -
https://helpx.adobe.com/download-install.html
You will need your serial number to activate the installation. If you have no record of it then you might be able to find it thru your Adobe account online. If you remain unable to locate it, you can try contacting Adobe support thru chat. If you/they can somehow confirm you own the product they might be able to provide you the serial number you need.
Serial number and activation chat support (non-CC)
http://helpx.adobe.com/x-productkb/global/service1.html ( http://adobe.ly/1aYjbSC )