We are selling online. We want to give a money back guarantee if the customer does not like our product. However, we're afraid that we may get many returns due to customers misusing our promise. Then, we will lose money for the shipping cost and other charges. How can we avoid this?
Instead of money back guarantee offer a "110% of your money back" guarantee in the form of store credit. Use a third party to process returns and make the customers jump through hoops so you can play dumb and not be the bad guy. Add a non-refundable handling charge for returns. This is what small print is for.