In California direct supervision is not required at all times. My license is small so I don't have to have an assistant. And I gotta use the bathroom once in a while you know? I make sure the kids are busy, and my troublesome twosome are separated in playpens, and I go potty. I also go out to open the gate across my driveway at the end of the day so parents don't have to park on the street. I grab the mail while I'm out there doing that.
I wanted you to know regs so that you aren't surprised by similar circumstances at another daycare. You wouldn't find someone you didn't know about taking care of your kids at my house...but you might find me walking out to check the mail and open the gate while they are in the playroom.
Someone with CPR and FIRST AID needs to be onsite at all times....this means somewhere on the property. My 17 year old son (incidentally is on the Sheriff's dept search and rescue team and has more medical training than I do) takes care of a small group when I am ill...but I'm onsite. He doesn't do diapers unless he's paid extra so he brings little ones to me to change them, but he can do the rest and is awesome at it. He is frequently begged for his babysitting services at my client's homes on their date nights.
But, if your provider's response made you uncomfortable, you should certainly find other care. Parents need to go with their gut.