Hi Chris, I'm pleased to assist you. There would be instructions inside the shipping box where to return the core. You may use any courier and make sure to keep the tracking number as proof of return. Once we receive the part, our Accounting Department will credit the amount to the card you used to purchase which would take about 3-5 business days to process. Your banking institution will take another 3-5 business days to post the amount back to your card. Click on the link below to order at 57% off the regular price while supplies last. https://www.carparts.com/alternator/quality-built/mpa13531?can=CPGG4850 I hope this is helpful. Enjoy shopping at Carparts.com!