Mageblood disappeared from Ange

I put up 2 Magebloods for sale at my Ange and one ‘disappeared’ without payment. Someone TP’ed to my hideout to buy the first one, then a couple mins later someone else TP’ed in and the second one (freshly dropped) disappeared.
If anyone has any idea what I did wrong I’m all ears. On my sale log only one (the old belt shows). I was trying to sell mine and the new one to buy a better belt.