I bought a used Sigma 170/500mm lens online from Roberts. By my own mistake I ordered the wrong lens. I assumed the lens was AF, it was not. I checked online and Robert's had the lens I actually wanted and should have bought. One call to Robert's customer service and they advised me to return the lens and I would get a full refund. Shipped the lens back and tracked it via USPS. Tracking showed the lens made it to Indianapolis but no verification of delivery. Another phone call to Robert's and they quickly verified that they had received the lens and the correct lens had been shipped out to me. Same day got a verification that my credit card account had been credited the original amount. The whole process was seamless, other than my original mistake. Will be buying from Robert's again in the future. PS: The new lens works fantastic.