I have been thinking about taking the Station Casino offer of the free cruise for the past six months but cannot get past the offer that is supposed to be "free", yet expects me to pay $100 per person to book. I too called the customer service number and was told that the initial $100 per person would be returned in OBC. If you upgraded to a balcony then I think you paid the premium to upgrade plus the $100 OBC deposit. At least that how the pricing looks to me. This is one of the reasons that I did not book yet, you cannot get a definitive answer.
On the booking site it shows $0 for an interior and $315 for a balcony, yet when I do a mock booking it then shows $100 per person for an interior and $415 for a balcony. Doesn't that seem to you that they are charging the $100 for the deposit plus the cost of the balcony. Is this what you paid?