Well received your comments.
We will be checking back to the source of the problem and resolve it asap.
Our system (of inventory management) has been being developed and renovated this passing year, so this unavoidably affect to our work-flow and process. Of course,it affects to other accounts too.
But in the near future, the system we are now developing will be very helpful and simplify work-flow with less mistake.
We understand our good relationship is important and we are also looking forward to growing our business together.
Truly apologize for the inconvenience occurred and we promise to improve in the next year.