Spirit Air lost baggage mirmar Florida

Its been 7 months since I flew back home to Costa Rica from Florida. I had packed an irregular shaped and oversize package full of fiberglass fish mounts value at close to 4,000 USD. When I filed the claim I included pictures of the mounts in my mothers home and pictures of the fish being caught by my late father. I also included a letter explaining why  I was using a Miami address instead of my CR address(the mail is not all ways reliable) so I use a fowarding agent in Miami Florida. They told me they could not process the claim unless I used the CR address on the form and would not change it for me I had to spend another 35 USD with the correction. I waited several weeks and no letter, I sent them an email and phone call they said they they had just sent it out to the miami address that they refused in the first place, so I waited again and no letter. I called again now we are are 6 months, they returned the call and I was instructed to send an email requesting they email a copy of the lettter and I waited again after a couple of weeks they finally sent the email denying my claim. I have since requested from them what they need to process my claim, They sent me an email stating that I had the right to contact any agency I wanted to try to settle my claim. I live in Costa Rica now I am looking at a trip to florida to file a small claims against them and a return trip to go to court not to mention dragging my 74 year old mother to florida from Tenneesse as a witness that I did indeed pack up the said contents of the package its not the trip its also the memory of my late father and the fishing trip that she was on when the fish were caught by my father, she just wanted me to have the mounts in my home in Costa Rica. In the end even with all the right paper work filed with Spirit they have never once acknowledged losing my package. how is it that people can do business like this and do it on a daily basis. They want me to trust them with my life by flying with them but thats all they offer ,so it makes me wonder how much my life is worth to them