This was our first cruise and it was an awful experience. We left New Orleans at 6 p.m. Sunday night. Monday at 4 p.m. they told us a passenger was ill and that they we going to turn the ship and go to Key West instead of Jamaica. They said it was an emergency. We were only a few hours off the Mexican coast and no one could understand that if it was an emergency why  they did not either heliport her out using the heliport pad on the ship or take her to the nearest port to heliport her out. We traveled 20 hours to Key West and when we got there- there was no place to port the ship so we had to stay out in the water off the coast for an additional 4 hours. Then we had to stay in Key West for 8 hours. It took us another 20 hours at sea to get back where we started from. There were a lot of upset people on board- everywhere you went they were discussing that they could not understand what was going on and how awful this had made the cruise. I went to the pursers desk and told them that I wanted to use their "Guarantee" and get off the ship. Their guarantee states that you can get off at the first port for any reason and they will fly you back to your departure port and refund the balance of the cruise. I asked for this before we got to Key West. I was told that if I got off at Key West, I would have to pay over $200.00 additional in port fees, receive no refund on the unused portion of the trip and pay my plane fare back to New Orleans. They said the guarantee did not pertain to U. S ports , even though they had substituted a U S port for Jamaica. Then I asked if I could use the guarantee at the first foreign port as their guarantee stated. They told me that I could get off at Grand Cayman but I would have to pay the airfare back to New Orleans and I would not be reimbursed. They said they did not know anything about Carnival paying the airfare at all. I went back to my cabin and got their booklet with the guarantee in it - but they still told me no. I went back to the room and got their comment card and stated on it what had happened- hoping I would get a response when I turned it in- but I got nothing. When we got off the ship in Key West I sent a post card to my travel agent telling her what had happened. When we returned home I called our agent […] and she said she would contact Carnival. She called back and said she had talked with […] at Carnival and she was sure they would make everything good. […] called me and I told her the entire story. She apologized and said we would receive compensation. I got the letter from her 2 weeks later and it said we would get 10% off on our next cruise. I was shocked. I expected them to treat me fairly and felt there must have been a mistake so I called back. I was rudely told that there was nothing they could do because the guarantee had to be used while we were on the cruise - not afterward. I told her that I had tried to use it but the pursers desk had refused to honor it. She knew I had proof that I had tried to use the guarantee but she still did nothing. All I wanted to do is get off the ship and re-take the cruise I paid for at a later time. I did not want to waste 50 hours going and coming to Key West. We went on the trip for our wedding anniversary that was Oct 16. After they refused to honor their guarantee- our trip was ruined. We did very little on the trip and stayed depressed the entire time. We felt used and lied to. We turned this over to Discover Card for investigation since that is how we paid for our tickets. I e-mailed the travel agent at Go travel back to let her know what had happened and she claimed she did not remember me. We had read reviews about Carnival and they were all good. Believe me when I tell you this experience was a real nightmare. One no one should have been put through. I am a business owner and my husband is a doctor - if we acted like Carnival we would be shut down. I hope enough people on our cruise complain - so this will not happen again because right now Carnival could care less.