HEALTH INSURANCE IS LYING ABOUT MY HEALTH!!!

hi, i recently was denied by a health insurance company supposely they say when they got my medical records they find out that i have heart arrythmia which i call me doctor right away because on october i was having some breathing problems and my doctor send me to see a cardiologist so i went but he told me i had heart burn which i was not happy with the answer so i ask for a heart monitor a month later i have my results back and they were normal. When i call my cardiologist he told me that the insurance company never asked for my medical records, so i called then furious and supposely they did got my medical records but they want it again so i did when with my cardiologist and got them. I did send the medical record and the health insurance denied me again now they say i have a sinus arrythmia!!! I really need a advice on what to do . Im very streesful because i really need to have health insurance. also my husband and son were accepted but i didn,t please help!!!!