Have you equipped the full set on one and the same character?

After buying and claiming something from the market, normally a time frame runs down for when the item becomes free, aka possible to be bought and sold via the in-game options, like mail, character to character trade and the GTN. If you want to use it for yourself, you can just use it immediately.

So for saving something into your collection you need to use or equip the items, in case of an armor, bind the full set to one character. Only complete sets go into collections and only if you equip it on one and the same character.

There are (or were) a few armor sets that have stats in them, those not going into collection is working as intended, as far as I know, since at least in the past they could have been abused to gain an endless supply of those modifications.Though without knowing which armor you bought it's impossible to tell if that one might be one of those special cases.

So for saving something into your collection you need to use or equip the items, in case of an armor, bind the full set to one character. Only complete sets go into collections and only if you equip it on one and the same character.

There are a few sets (no more than a partially-amputated handful) which have two chest-armour pieces (one with a cape, one without, or one with a hood up, one with it down). In the case of these sets, "bind the full set" means *both* chest pieces.

There are (or were) a few armor sets that have stats in them, those not going into collection is working as intended, as far as I know, since at least in the past they could have been abused to gain an endless supply of those modifications.Though without knowing which armor you bought it's impossible to tell if that one might be one of those special cases.

At the moment, I believe that none of these sets are available on the CM.

There are a few sets (no more than a partially-amputated handful) which have two chest-armour pieces (one with a cape, one without, or one with a hood up, one with it down). In the case of these sets, "bind the full set" means *both* chest pieces.

Or in the case of the Malgus Reborn set, both head pieces/masks.

Or in the case of the Malgus Reborn set, both head pieces/masks.

Correct, yes. I forgot about that one.