I check my call logs periodically and see that this caller is persistent AND stupid. Since I've blocked the number here is their attempts to call despite being blocked: 3-24-17, 6:03–6:04pm, 6x (6 calls in a row); 4-12-17, 5:45–5:46pm, 6x; 4-17-17, 6:48–6:49pm, 5x. That's 17 tries despite not getting through at all! Glad to hear that it's that car warranty scam; I'd been curious.
Called today saying they were Dealer Support Services selling auto warranties. I asked if I could have their phone number. The guy on the phone insisted they didn't have a phone number. I asked how he could possibly think they were a legitimate business with no way for customers to contact them. He tried to convince me they were a legitimate business and told me to google them. Okay, why not. This is what I found http://www.dealersupportservices.com. At that point, the caller abruptly hung up.