Same problem here with ARK
If you need "cash" to trade, no other solution than to sell as is, mark a loss, and try to compensate on other pairs.
A trader always loose; the important it to gain (a bit) more than you loose.
If you don't need immediate cash, place manual orders on the marketplace with a tiny margin, or a decent loss (like -5% for example, if you're already far below...)
Third solution, leave your bot trying to sell them - but it'll take a long time and a load on the API...
Good luck!