Smart Travel and Incentives Smart Travel Refused not a honor voucher that was given to my family Lake Mary Florida

My family (2 adults 2 children) were given a voucher for a stay at an Indoor Amusement Park for attending a timeshare conference. I had to mail in the order form with the voucher and a money order. I orginally called Smart Travel because I wanted to make sure that I was sending the money to a legitimate company and they went over that I needed to make sure i did not send a personal check and it was money order or certified check. The woman never stated to send it certified mail. Therefore I sent the money order and voucher in on September 3, 2014, now on October 6 2014 I received my mail back with a VOID stamp on it that says because it was not sent "certified mail" that the trip cannot be honored. Their return envelope has a letter inside and at the closing there isnt even a signature just "Smart Travel & Incentives" typed with a different address than the one I sent my mail too. I than called Smart Travel to speak with someone that could clarify my confusion and I get a rude woman stating that it was in the small print what the regulations were. (Now mind you my son has been getting the mail everyday after school waiting on the return mail so we could book the vacation and now this??) I tried explaining to her that on the original mail in form it just says to mail form to.......... nothing about ceritified mail and she cuts me off telling me there is nothing she is going to do so I than ask to speak to her supervisor and she says, "I am the supervisor" so I assured her that I am certain that she has a supervisor and she told me that she could try to transfer me to her but "her boss" would just put her back on the phone. I knew than that I was just getting a run around!! Its a shame because if all was well we were going to look into using them as a travel agency because we do traveling twice a year and are need of a new agency but it is evident that customer service is not where they specialize at.