call their customer service, don't use the web chat
"Solid signal sent the wrong item, (a 3-stranded thermostat wire instead of a single heavy duty grounding wire) and when I contacted them via the online chat, the agent cited a 30-day return rule. So I did delay opening the package, since I didn't do the project right away. I found that frustrating, since it was the wrong item. I then called and the customer service by phone was great. Very helpful, worked with tech support, and then sent me the correct item."