Native Sun Pools

Purchased a Pentair Triton TR60 Sand filter from Native Pools after being informed by their tech that my present filter was defective. The old filter was pushing dirt back into my pool after vacuuming. With the new filter I have the same problem. I was informed by one of their techs (Greg) that the filter was installed incorrectly and the filter media was not correct for that type filter. I have since attempted to have someone come out and fix the problem to no avail. Native Sun has informed me that Pentair is responsible and that I need to reach out to them. You would think that Native Sun since they recommended the filter and installed it would stand behind their work. They will not and do not return my calls.