I had my pool re-plastered because the plaster was too thin to clean properly, and so I had it re-plastered with a quartz plaster that the installer told me what much more durable. However, the benches on the pool and spa are extremely rough, and if I drag my fingers across the bench in the pool, they will bleed. Parts of the pool are smooth, and so I do not understand why the benches are rough. What can I do to repair this? I've asked the installer to repair it, but since I've already paid him in full, he is taking his sweet time.