Opposite of a deposit refund

I did put this in as a comment, but the more I think about it the more it seems to me it's the best option, so here it is as an answer that can be voted on.

I think forfeit is commonly used in respect of security deposits which are not refunded. To my ear this can function as a past participle/adjective even without the -ed suffix, but I suspect many might prefer the more "grammatical" form.

EDIT: As suggested above, will be forfeit has been gaining traction against the "regular" past participle / adjectival form will be forfeited. As this NGram shows, the noninflected form now accounts for 2 out of 5 BrE usages. The shift is less marked in AmE, but it's happening there too.

Is this like a security deposit (when renting property)? Since a security deposit isn't usually binary—you can have part of it returned and part not to pay for damages—would you be better off thinking of this as "amount returned" (and zero means you kept it all)?

If it really is binary in your case and you don't like kept, consider retained or not returned.

I would say Used rather than Kept. This aligns with the basic idea that the only reason not to return deposit monies is because they needed to be used for whatever purpose the deposit had, and makes it sound a bit less like "oh, hey, we just decided to keep this money". If you wanted to go slightly fancier, you could say Expensed, as in "used to cover an expense".

If you mean that the order is completed, so there is no longer an opportunity to return the item for a refund even if it gets broken, I'd suggest completed or fulfilled to describe the order status.

Hold [hohld] /verb (used with object)

2. to set aside; reserve or retain.

Source: Dictionary.com

I would say, "held".