30-Day Tanning Membership Purchased but only 29 Days Received

I purchased an "unlimited monthly (tanning) package" in Oklahoma on March 15, 2015. The package entitles me to "30 consecutive days of tanning". No contract was signed. The salon notified me after the fact that they would be closed on Easter Sunday. Due to this holiday closure I will only receive 29 of the 30 days for which I paid. In years past, the Salon added an extra day to my package for any days when the salon was closed for a holiday or had closed early because of inclement weather. But when I asked about it this year, the manager stated "we aren't doing that this year". By law isn't the Salon obligated to either give me the 30 days I paid for or prorate a refund for any days I don't get to tan because they are closed?