Generally you have a few options here.
The first would be to report the issue to the local code enforcement. it sounds like you have done this, although you might check around to see if there is a different government authority than the one you have been talking to. Sometimes just getting the correct department can make all the difference.
Next would be to check with your insurance company to see if you have some sort of claim here. Sometimes they have ways to assist.
Last would be to sue your neighbor. This is never a great option, but at times it may be the only one and it sounds like you have solid grounds for a case.
One last idea if you haven’t already tried it would be to make a deal with your neighbor in some way. It sounds like they won’t just stop, but maybe you could offer to buy the property or offer them some sort of financial incentive to stop their operations. Although it’s not fair to you, it might be cheaper than a lawsuit.