No customer communication

I ordered a CPU cooler and thermal paste with delivery fee of R49. They delivered the thermal paste but not the cooler. Almost a week later after following up multiple times now they do not have stock of the cooler. So basically I pad R49 delivery fee for R165 item. Why do I have to follow up with them couldn't they have the courtesy to phone me and state there is no stock even though the website clearly stated there was stock and after finally speaking to somebody that 2 were on their way to my area. Again had to follow up only to be told now stock.