Solution for customers to claim compensation from Chinese suppliers after the after-sales period of the product has passed

One is: What is your product and is it possible that the storage environment (such as environmental humidity, light intensity, etc.) will affect the color difference of the product?
Secondly, do you have any remedial measures to help customers minimize losses in addition to claims regarding the current customer complaints?
Based on your description of this case, it seems that you have no major issues at all. Whether it is in terms of process or timeliness, you are all OK. This kind of communication must have a firm attitude, a gentle tone, and even send a small portion of the goods together. It is not your responsibility to ship together next time. If you are willing to do so, it is because you value your relationship with customers, not because you have done something wrong.
This attitude needs to be firmly conveyed to the client, and it is recommended to follow the email framework as mentioned above. The email can be written as follows:
We are sorry to receive your feedback, but unfortunately, after internal confirmation, we may not be able to bear your claim.
The product was shipped 2 years ago and the quality standards had been confirmed by your company (or designated commissioning party) before we released the product. Therefore, our goods meet the quality standards of both parties, which is a consensus. Otherwise, your company may not agree to release the goods, right?
Furthermore, to put it a step further, the default warranty period for this product in the industry is one and a half years at most. Even if I try to fight for it for you, it does go far beyond the regular warranty period, and I am afraid I am also powerless.
Now that you are filing such a high claim, it is obviously unfair to us. Even if I personally want to share it with you (meaning I am helping you), we believe that there was no mistake on our part in the entire matter. Could you please discuss and confirm with your colleagues’ team how we can help you in other aspects? (Attempting to divert customers’ attention to other dimensions)
Similar to this kind of firm attitude and gentle tone, the feeling is about to come out.
This is your problem, I am anxious for you. I can help you solve the problem, but it is because I am a good person and I value you as a customer, not because I did something wrong.
Then the remedial measures you propose should also be called upon in a thousand ways, rather than being given to the customer from the beginning, which may appear guilty.