Renew Subscription Purchased Through School Fundraiser.

I would like to renew the subscription of "Seventeen" that I purchased through my daughters school fundraiser last year. You have mailed me a renewal package offering:                                                                            a 3 year subscription @ $18.00, and a make-up kit                                                                              but the school has sent home a flier asking that if we renew to please use this code - WB5113- so that they will recieve credit for the sale, but there isn't any where on the renewal form to enter any code. Can you help me with this? My name is John Harriss and the subsription was ordered for my daughter Heather Harriss Account# SVN1253289084