The crystal I bought has not arrived. Who should I contact?

The in-game help button can sometimes be helpful for missing purchases but for most things it is not very helpful, mainly because it doesn't maintain a record of the conversation independent of your game data and you tend to be bounce around between different support staff if the conversation lasts longer than one day which means explaining everything over again.
I would recommend using this ea answers site for much better support.
https://answers.ea.com/t5/STAR-WARS-Galaxy-of-Heroes/ct-p/star-wars-en