Just make the swapped gear come with an augment sot. This way your only loss is the augment extraction (to be done prior to swapping).
This is something I also hope they do (or find another solution at least for the augment slots).
The point I tried to make is that this is a mechanism that is not yet in game. All current: "Trade item for item" systems in TOR do not take Augments into play. Depending on how Augments were implemented in game when they were added earlier this year it can be a very hard thing to recognize the slot in the item while it is being traded and then change the trade to have that specific augment slot.
Not saying it's impossible, just saying it is more complex than "just". Often in Software development, something that is very easy and simple to define, like this, can be very hard to develop and implement because of earlier choices made in the development cycle.
I just want a refund, including the cost of ripping out the mods of the old pieces, augmenting etc.
This might be possible, but then again.. these are also merely ingame credits. I think the real issue here is real money. Which comes to your next point:
Anyone would paid real life cash via cartel coins needs and deserves a refund to their credit card.
The problem here is the following: How can you, as a consumer, prove that you spent money on Cartel Packs just for this specific item? I believe this is nearly impossible to prove and, again, you received many other items in those packs that did have their advertised worth.
This is exactly why any reparation that needs to be done, should be done on the items themselves. Giving money back is impossible because there is not a single bit of proof of what amount of money was spent for those items specifically.
Creating a situation where people can return the items to their original look seems to be the best solution for all parties involved. What will happen with augment slots and other ingame credits spent on this.. that is one thing that depends on many factors, including what is technically possible in the short time they need to fix this in, as I tried to explain above.