When you return a product - if you have made no other product purchases from that brand -  you are No longer able to share a link for that product or receive any Kwikcash for purchases made with a link you may have sent before refunding the product.  

If you have purchased from a link sent by a person who has returned the product, but you have kept the product, your waves and campaign will continue to work, and you will still make Kwikcash from purchases made from your link.