Coupon using Membership2 Pro

I am using Membership2 Pro for a "box subscription" site. We sell subscription memberships for women's clothing at a cost of $60 per month. I launched the site with a promotion using a coupon. The coupon entitled the user to their first box for $1. However, I've noticed that anyone that uses the coupon is charged $1 for the first month as is suppose to happen, however the reoccurring charge will also only charge them $1. How do I change this to make it only applicable for the first month?