Poor service

Afribuild I have purchased materials before the 14th of December 2020 and I was told that some of the things are not available and that I should wait for January, it was not a problem I waited and never got a call from Afribuild Matatiele. It happened that I went home and I passed by last week to check and I was told that the material came and was sold. Please advise me on what to do on this matter. They have an option of either delivering whatever that is available so the work can continue and they can deliver the rest whenever they want at their cost....