Mistakes happen to every supplier. The US customer judges you not by the absence of a mistake but by the speed of fixing it.
In American business culture, the speed of responding to a complaint is a measure of trust. The right response within the first day: confirmation that you took the matter seriously, what you need to resolve it, photos and batch numbers, and when you will give an answer. Not yet a solution, but a firm process.
Silence or a defensive stance in the first message is the beginning of the end of the relationship, even if you are right.
For small amounts, decide quickly and generously: a credit on the next invoice or a replacement with the next delivery costs less than a dispute. For large ones, gather the facts, involve the insurer, but keep the customer in the picture at all times.
And always: root cause and corrective action in writing. A US buyer accepts a mistake that happened once, and walks away from a supplier who makes the same mistake twice.
It sounds like a cliché, but the data confirm it: a customer whose problem was well resolved is more loyal than one who had no problems. They have seen you under pressure, and that is information no price list can give.
The first consultation is free: together we'll see who in the US already buys your product and how to reach them.