MSC CHANGES TERMS OF "#netMATRIEKS" TRIP - false advertising & no refund

We booked a trip for our son who's in Matric this year on MSC Cruises and paid a deposit of R3 000 in March 2021. (booking number - ***) This trip was advertised as the "#netMATRIEKS2021" cruise meaning that ONLY Matriculants would be going. Subsequently, after we paid our deposits, the trip then changed to include first year students. My son and and his friends decided to cancel their trip as they were not keen to share this experience with students as this would change the dynamics and interaction on the trip. I then requested for my deposit to be refunded with a definite denial coming through due to the fact that it's in the fine print; "no deposit will be refunded." Now my question is why MSC Cruises get away with not returning our deposits after the INITIAL terms of the trip was changed and advertised as a "#netMATRIEKS" trip. This constitutes as FALSE ADVERTISING! Why should we as parents pay the penalty for this? I have written numerous e-mails to MSC with the same response that they won't refund us. There are many other parents who share the same sentiment and are also furious for not being refunded. Shame on you MSC Cruises for not refunding our deposits! I will most certainly not make use of your services again.