Is $12,000 to complete a full drain, waste, vent re-pipe a fair price?

I hired a licensed local plumbing contractor to complete a full drain, waste, vent re-pipe. After experiencing persistent drainage and venting problems for over a year, I discovered that the work had been completed without a required permit. An after-the-fact permit was eventually filed, but the inspection is currently in a failed status. Despite more than ten return visits since the project was declared “complete,” the venting and drainage issues remain unresolved. The city is now involved due to the retroactive permit filing. Since the inspection failed, the contractor is SUPER slow to communicate with me. The city inspector said that inspections should have happened at multiple points during the work. I’m trying to understand my options regarding unpermitted plumbing work in this situation, especially with a failed after-the-fact permit. I submitted a formal letter to the contractor requesting a clear path to resolution, timeline, and/or refund/compensation just over a week ago, but I have received no response. I definitely have a paper trail including email exchanges, text messages, voicemail messages, records of all the return visits, and videos of bubbling toilets, not to mention the failed inspections following the after-the-fact permitting. I think it’s time to file a complaint. The company knew the permit was needed and should have pulled it, but they did not, and pulled the permit and submitted the notice of commencement after the fact. After I continued having issues after the work was completed (with no fixes after many, many return visits), I looked into acquiring a copy of the inspection report, admittedly after the fact, only to find that there was no inspection because a permit was never pulled. In my county (in the state of Florida), to the best of my knowledge, the contractor, not the homeowner, is normally responsible for pulling permits when a licensed contractor is hired to perform the work. The work was done by a not-so-small regional company that also has a ton of turnover.