3 day delivery is 3 weeks delivery with PEP and PEXI

On the 18th of June 2020 i asked my friend to collect something and send it via PEP George Sandkraal road on the 2-3 days delivery so the Items were too big to fit on one bag so he bought two bags after three days I received 1 parcel when I asked about the second one they said it will come with another courier. I did not understand why two parcels who were sent at the same time by one person must go with different couriers but I decided to be patient on Sunday the 28 June 2020 i called them to find out where is my parcel they told me there is an error with the scanning number so it does not scan so they can give it to the courier a ladies called Phumla called me to give me feedback on Monday saying there is an error with the scanning number but they will resolve it she has told the courier to go and collect the parcel but I called the store today they told me the same story that the is a error with the scanning number the problem is with PEXI and the Courier. Tell me why is it my problem that they made a mistake and I PAID for a delivery of 3 days instead I am still waiting almost 3 weeks