Post office

We have been going to the post office to certify documents now all of a sudden when you go to the post office they either don't have a stamp , or they tell u to go to the police station or they are busy with the 350 que. It doesn't make sense to me that they don't want to certify anymore I've been to three Jabulani mall, Dobsonville point and maponya mall. So what I really need to know is why do post offices not certify anymore