Thier failure to pronounce your name properly could be due to any number of factors: lack of respect or shared concern is one/two of them, but just one/two.
It could be a group mentality thing--either consciously or sub-consciously, they mispronounce it the way others mispronounce it to follow their management or the dominant employees, to fit in, or simply not stand out.
I think it's important to remember that in the U.S. there is a large variety of different dialects and accents, and the way people from any of them hear and pronounce something could vary greatly. It could just be a huge mismatch--as in, they'll never hear the nuances that your trained ears do and/or they'll never seem to master it no matter how hard they try because of what they grew up with or where they live. While almost all of us are born with the ability to master the language(s) we hear and speak first, certain muscles used to make sounds relatively unique to some other languages may atrophy and those doors of opportunity effectively close. Since you're bilingual, you have abilities others simply may not, and depending on the language, never may have. If they think your name is really that unusual, it could be that your pronunciation actually does sound different to them because it is inherently different--they can't hear the resonance that occurs inside your head! Everyone has an accent.
I'm sorry, but the correct pronunciation of your preferred name may never happen--at least not where you are now.