For you trade pile problem any of these may be your problem, any cards that have a green tick on them need to be cleared by pressing y (possibly for each one, or may all go in one hit). Any cards that are up for sale and are active you cant do anything with them untill they are sold/unsold. Any unsold cards can be relisted or by pressing X give an option to store in club or quick sell. You can only hold around 30 cards in your trade pile at any one time regardless of sold, unsold, active or available items, hope that helps.