I have contacted the senior manager of DHL Hong Kong office for enquiring further and clarifying the problem, they claim they will follow up the issue and will avoid the problems happening again.
They also stated that your company has an instruction of "not allowed to post to third party", but the officers keep mess it up two to three times as "not allow for export". So it's no problem for us to delivery to your company. Thank you very much for your company further authorisation. We will keep you post when the samples are ready to ship to you. Thank you.