If you can't ship when promised, you must notify the customer of the delay and the right to cancel. For definite delays of up to 30 days, you may treat the customer's silence as agreement to the delay. For longer or indefinite delays, and second and subsequent delays, you must get the customer's consent. If you don't, you must promptly refund all the money the customer paid you without being asked.
Affiliate marketing is commonly confused with referral marketing, as both forms of marketing use third parties to drive sales to the retailer. The two forms of marketing are differentiated, however, in how they drive sales, where affiliate marketing relies purely on financial motivations, while referral marketing relies more on trust and personal relationships.