Significant currency missing after transfer

I’m missing all of my undercoin after moving it between characters. I sent part of it over to this character and used it to buy some items, then tried to send the remainder back. The character I initially sent it from had 21991 undercoins and should have had 18,366 after the transfer back. They had 0 after trying to send it back, and the current 911 count comes from what was earned this week.

That’s a significant amount of currency that’s just gone after sending it between characters. The resonance crystals and Kej were returned and sent to another character but the Undercoin was completely deleted.

While trying to transfer it there was an error of Transfer in Progress, please try again later, but it reduced the currency count anyways and now its all gone (apart from what was earned this week).