I had the same issue shipping engine parts to Arizona by air freight. They claimed they contained fuel. I said you're wrong. They still refused, so I figured two can play this game. I filled out paperwork declaring them radioactive, and after sucking up two hours asking for assistance
at every step, we got it done. They assured me it would be shipped overnight. Two days later they called and asked me to come in and speak with them. They had not shipped them, admitted they lied, and asked me to withdraw the paperwork, and promised to ship the parts.
This time they did ship them.