Delivery is just not happening

My son is a home schooling learner, using Impaq's study material. We registered him for 2018 and made the necessary payments in Dec 2017. On Dec 15 we received notice that his school books are dispatched for delivery.

As of today (14 Feb 2018), we did not receive it. I called Impaq's Call Centre three times already. The first gentleman assured me he will inquire about the delivery and I'll be receiving a phone call from them with an update. This did not happen. Then I spoke to a lady who said the package is lost. She then proceeded to order a new set of school books, marking it as urgent. According to her assurance, it would be dispatched today.

Today I phoned again and spoke to a third person, another gentleman. He said he would inquire into the delivery and I'll be receiveing a phone call. This did not happen.

When I logged in to my son's school records, the only record of his school books is the delivery note of December 2017. If you click on the Dawn Wing Waybill Number, you receive the message that this Waybill Number doesn't exist.

In the mean time the first term is almost finished and my son haven't even started with his school year yet, due to Impaq's terrible service. We are getting very desperate and, to be honset, rather upset.