Why my orders was cancelled in DEX? How much does it cost?

There are two types or order placement in DEX, namely as GTE order (Good Till Expired) and IOE order (Immediate or Cancel).

By default, orders will stay valid within one million's block time (approx. 30days), feature fee will be deducted by the duration of order placement and it'll return systematically if they're any extra left before it's expired in the period.