False Promises to Get Sale

I bought a 2nd hand CRV from Honda Rivonia about 3 months ago and on buying the car I insisted that they include a cover for the boot of the car because my wife drives through some dangerous areas on her way to work and she always carries things in her boot. At the time of purchase I was promised a cover and that it would go on back order which would take about a week. I waited for about a month with no feedback and so I followed up myself at which stage I was assured that they were getting it to me at the end of that week. Again I waited and about 2 weeks later I followed up because no-one had the decency to call me back and I was told one was found but they were waiting for it to be delivered and they would let me know by the end of the week. Again, the salesman didn't get back to me and so I spoke to his manager, Andrew, who promised me he would have an answer by the Monday and I would receive the cover the following week. No-one phoned me on Monday and so I phoned on Tuesday at which stage the salesman explained that they had prioritised the matter and it would be at the end of the week. Another week has now passed and no-one has even phoned to let me know what is happening????