It is not uncommon for a gunsmith to get stuck with a completed or partially completed project only to find the customer is not willing or not able to come up with the funds. So it is understandable that most will ask for a big deposit. However, any good gunsmith will identify his terms up front and restate them later if asked. He will also return your parts if you do not wish to use his services. It would cost only about $15 to ship an action back to you.

I would both email and snail mail the gunsmith advising that you are having UPS or FedEx issue a call tag for him to return the action to you. You can pay those companies to do that and they will pick it up at no cost to him. If he insists on any payment then you insist on getting both an invoice for work completed and a copy of your authorization to perform the work. He can hold the action for payment but only for legitimate charges. You are entitled to an invoice and he needs to produce something showing you requested to or authorized the work he performed. For example, you may have inadvertently agreed to a minimal service fee. If so, he needs to show that you did.

The bottom line is that he isn't happy with the payment plan you want. He should have explained costs and terms BEFORE you sent the action and at this point he should be bowing out gracefully and doing the right thing by sending your action back to you. Please PM me the gunsmith's name. I will keep it to myself but I just want to make sure that I don't deal with him.