Hi. I also recently tried to contact ServicePlus Home Warranty customer service, but since these guys are not very popular, it was very difficult to find contacts online. Fortunately, a friend of mine recommended me to check out this website https://serviceplus-home-warranty.pissedconsumer.com/customer-service.html where I was able to find the phone numbers and email of this company's customer service.
I hope my answer will help you!