[US] ER-Bill.com. Got a bill from them for an ER visit and it seems sketchy.

A family member received a $28.40 bill from ER-Bill.com for an ER visit in December, with a final notice threatening collections. The company's website displays a certificate error, and attempts to contact them via phone have been unsuccessful. The user is skeptical of the site's legitimacy despite some online sources labeling it as safe.