Independant contractors. They are found from the classified ads for, "direct home sales" "closers only need apply" "$70,000+ a year" "No overhead required" "we supply the leads" "Factory Direct Sales"
They come in, stay long, promise everthing, close the sale, then it is shippped and the consumer does the rest.
When you have a problem, they contact a local service out of the yellow pages, and good luck from there on.
If you do not buy their internet chemicals etc, be wary of what voids your warranty.