Failure to deliver courier on time

On 12 Dec 2017 I arranged for DHL courier to deliver documents in China. I was informed this process will take place within 2-3 days on this parcel should have been arrived on Friday, 15 Dec 2017 already. No one contacts me at DHL to inform me of this delay. Their tracking site doesn't inform me either. This delay is delaying another process. Next time I will not use this service because they are not true to their service level.