That would be my next thing to say - if you bail out from your US insurance now, it would be very difficult to get it back once you return to the US. Oh, the joys of moving abroad...
I also have a chronical condition, and i ended up by paying the private insurance i had back in Spain, and have restricted policy in Switzerland. You will allways get covered by the basic insurance (i.e. Kanton Hospital....), but they can cut your legs on the private ones and whatever extensions you may want to have. I had to provide them some medical records and statements from my doctor for the the pre existing health cause. Actually, i do prefer not to change medical teams at this point of my life...
All i can recommend is to hold firmly your US policy and have a lot of patiente when handling with the insurance company in Switzerland untill you have things sorted out. The older i grow, the more I understand that medical questions should not be left to the mercy of for profit companies...