Slow delivery of registered mail

I received today, 26 January 2018 two registered letters at the Sinoville post office. These two letters were mailed on 17th December 2017 at Centurion and were received at the Tshwane hub on 5 January. This is totally unacceptable, two weeks from Centurion to Tshwane hub, 20 days from hub to Sinoville post office. I needed these documents on the 19th of January for a meeting. the explanation I got when I asked about it, they were busy.....not good enough and really bad service.