If I were in your shoes, the answer would be simple. I am paying for a service. It should be done correctly. If not, they must fix it or are responsible for paying for it to be fixed or having it fixed if they cannot fix it themselves; it is something they caused in the process of things, and they are respsonsible. If they scooted around the issue after a few good-faith attempts were made at getting the issue resolved, than they would hear from my lawyer. Nothing less than that would be acceptable, IMO.

If I am paying for something, I expect to get exactly what I ordered. In this case, it would be a 100% level pool.