I experienced the same thing, but I just left my Millix on the sell order, and earlier it finally got hit. After that, I bought again and sold at a higher price. I only used a small amount of Millix to fiat to test the market and feel things out, and I check Fiatleak from time to time. Most of my other Millix are still on the Tangled exchange, placed at a higher price, and I’m waiting to see if those orders get hit as well.