Dave in Atlanta

Booked a future cruise while onboard MSC Seascape. There's a couple of significant problems with what we were told versus what we found out on our own after leaving the ship. Four different agents said "nothing can be done" and when I asked to speak with a supervisor was told there were none available, but I'd get a call back within 24 - 72 hours. So far no calls... Any ideas on how to get through to management to solve a simple problem?