Last year I had a couple of complaints in which I CALLED a Carnival Guest relations person and explained the whole situation with him. First let me stress that they also like praise in any area that you may have. I started the conversation with praising the people by name that went out of their way for me. They do get a write-up about this stuff and it goes towards promotions, raises, etc. After the praise is when I told him my complaints. I had it resolved right away during my phone call after holding online for a couple of minutes. I received a 10% discount on my future cruise to be booked within 18 months.
