Don't know the answer to your question, but Google finds
608-784-4570
associated with two different addresses
901 S. 4th St.
La Crosse, Wisconsin
and
571 West Ave N
West Salem, WI 54669-1078
Both addresses are different cities than the P.O. Box on the website which is
Onalaska, WI 54650
Could be all old information, and perhaps the company has moved once or twice, but you could try the number.
The Sapphire XLs have garnered rave reviews, and forum owners seem quite happy and loyal, so it might be worth your persistance.