Sorry for the late reply. We do have products other than DEF. As for our production line and packaging line, I have mentioned on the email of May 2, 2016:
“According to our factory policy, we are not allowed to use the same production line for different products in order to ensure the quality. In addition, we use different line for packing in order to avoid our products being mixed with unexpected materials.”
In addition, your client questioned about our producing standards. May I remind you that on May 2, 2016 I have also responded as follows:
“After confirming with our QC department, our record shows that this product you purchased from our company is qualified based on our producing standards, which is also showed on the certificate of analysis (COA).”
Since you did not provide us your client’s manufacturing process, we do not have enough information to figure out a reason that may cause the yellowing. We can only suggest that overheating should be the major reason.
You may forward our email response to your client, after all, we have no contact with your client and we do not think it’s appropriate for us to issue any letter to your client. However, we still offer the exchange of DEF if you would like, and that is including the shipping cost.
Please let me know if there is anything I can do for you. Thank you.
- Jul 30 Sat 2016 17:27