Wrong material delivered and late

For a building project I ordered numerous steel sections and plates from Macsteel. I ordered and paid the material on Wednesday morning 07/06/2017 and was assured that the delivery will be made on Friday 09/06/2017. Only half of the material was delivered on Friday and after much struggling the rest of the material was delivered almost 2 weeks later at 18h00 on Tursday 22/06/2017. Among the material ordered were a RS40 Galvanized Steel grid, but they delivered a mild steel one. I only saw this the next morning in the light. When I confronted them they said that they will exchange it, but that never happened. Because I could not delay my project any further I had to use the mild steel grid and asked for a refund. They said that they will give me the refund, but that also did not happen.

I am very disappointing with their poor service, there are many other steel suppliers which I would rather use in the future.