I sent through a POP on the 28th of February 25 but am struggling to get my items

I sent through a POP on the 28th of February 25 but am struggling to get my items. 4 textbooks and a Lenovo Notebook for my son. They say they don't have stock and are waiting for the items to arrived because they've ordered it. But they cannot give me a timeframe as to how long it will take to arrive. My son has an assignment due on the 20th of March and despite stressing the urgency of the items they simply do not care. I've been phoning since last Monday and on numerous occasions asked to speak to the manager. She just takes and gives messages. Today is the 11th and I'm still waiting for the items. Do they not have stock in the store at all, why must they order on request? And especially at the beginning of the year when they know there will be a high demand...this is totally unacceptable and ridiculous really