I was told by AA customer service that I could not upgrade on a CX flight using AA miles. Is that correct? Or would I get a different answer if I called CX?

Further question AA has special customer service numbers for its Platinum (sapphire) and Exec Platinum (Emerald) levels. I presume other OW airlines do as well. As an AA EP (which I will be atthe end of this trip) can I use other other OW Emerald customer service lines if I am travelling on their metal?

Thanks

Hamilton Guy