Class cancellation policy

I have had a few struggles recently with the class cancellation policy.
So, the new policy is that we get 90% of the class fees, and we need a minimum of 2 students. I agree with this, because with 2 students we get approx the salary we got before, with a nice upside potential if we have 3 or more students.
However, many of the classes end up having only one student. When I call the day of the class, and only 1 student has enrolled, the class should be cancelled.
First of all, whose responsibility is it to contact the student?
Second, the store manager doesn't want to refund their money, so s/he is insisting that I either teach the class for just 1 person (against policy plus I make very little money), or try to get the person to move to take a different class that either has one other person in it, or that has a potential to recruit for more people.
I have started writing in red, on the registration forms, "2-student minimum required." I also highlight the part for daytime phone number, because we may need to contact people that day. Additionally, I am telling students who want to enroll about the policy, and encouraging them to sign up with a friend to "guarantee" that the class won't be cancelled.
Any other feedback or suggestions on this? I emailed Jenny for clarification and she hasn't gotten back to me. I don't want to get crossways with the store managers, but this is a disagreement we are having, since I no longer want to teach just 1 person and make around $20 for 2 1/2 hours.
Thoughts?
Jenn