If someone has a complaint about a product, don't make them feel like they have to dig or pay more money to make it right. Extra costs can be negotiated but don't make it a priority when it's a returning customer. Make a separate visit to the location to discuss the concerns directly. Remember what your customer wants. The last time I had a sales rep in she replied with half of the products to be quoted. There is a difference between hearing the customer and listening to them. It's ten times more expensive to sign on new customers than it is to maintain customers.