Your acceptance of the damaged order created additional stress on you. Patience with a reputable caster, one that communicates, in most instances will achieve a satisfactory outcome. In the future, consider letting the transporter and the caster figure out their own problems, apparently starting with the caster not packaging correctly. Those two should "duke it out". Refuse to take delivery of damaged goods. Get a refund if necessary and go elsewhere if the caster and transporter can't get it right.
You were waiting to take advantage in the first place of the pricing that induced you to purchase as well as the caster's reputation for bullets that meet your needs. It is your money and your time (probably the more valuable is your time). Once your money transferred, you have the expectation of delivery of undamaged goods in a timely manner. Failing either of these expectations, you have the right to a renewed opinion of the caster.
Considerations for small business, which can also have bad days, is a customer's perogative. You are willing to offer consideration, bend but don't break, when the two-way communication is provided that assures you the small business is trying to accomplish their part of the deal. Failing the part about two-way communication when the limit of acceptable or agreed time has passed is where the deal breaks down.
As you said, you would have been willing to work with the caster, provided they just talked to you. The "sterile", one-sided, indeterminate environment without communication speaks volumes about that small business. They need to work on their business model and people skills.