Looks to me like those are not the same Conductive Fabrics that you were asked to deliver, but ones that you purchased from the market. When you take a delivery mission you MUST turn in the ones they have for you to pick up. The good news is that means you do not need to pay for them, at all....you are just delivering their items which they freely give you to deliver.
Items you are asked to deliver are special and indicated as such in the cargo panel; I don't see that indicator in your cargo screenshot and the mission screenshot shows you have picked up "0" (where it says "collected by you 0". That means you left the cargo back where you got the mission and must have purchased those conductive fabrics that you do have. You'll need to sell those somewhere, they won't work for the delivery mission.
You pick up that cargo from the mission board of the originating station, exactly like what you had to do for the delivery problem you had earlier, so you need to go back to the station where you took the mission and get the cargo from them.
Also, if you get blown up or something after picking up the original cargo and lose the original cargo, you have failed the mission. All you can do is cancel it, you cannot complete it. When someone asks you to deliver something for them, losing it is not something you can cover up by purchasing more of the same material.