I am not a teacher, but here is my suggestion:
As brought to your kind notice in the past, We are still receiving the stained equipments. The grease is stained on the boxes shipped to our customers in USA. We have been penalised with penalty fees and new boxes by our customers. I am quite surprised by repition of such instances at your end.
I would request you to kindly look into this and suggest or take actions to avoid such things from happening again in future.
Your prompt reply on the above would be appreciated.
Student or Learner