Re: tax tab is missing of show only low tax tab

I'm not sure what's happening - different upgrades to city hall unlock different things. https://www.ign.com/wikis/simcity/Town_Hall  It should unlock for all cities in the region. But, if you close or bulldoze city hall or any of the departments, it will take those unlocks away. 

If it doesn't seem to be working, you could try repairing the game. To try to fix local corruption, follow these steps:

Exit SimCity and Origin completely.
Launch Origin "As Administrator" (Right-click Origin.exe, choose Compatibility tab, Check the box next to "Run this program as administrator")
In Origin, right-click the SimCity icon and choose "Repair". Origin has to be online for this to complete. Let the repair run until completed.
Launch SimCity "As Administrator" and check to see if you can load the affected city.

Corruption can happen if there is an interruption in the synchronization process, or if something like antivirus or firewall is preventing communication, so always run Origin.exe and SimCity.exe "as administrator". Be sure both are added to exception lists for antivirus and firewall. Try using a wired connection instead of wifi if possible, to reduce data communication errors. Good luck and Happy Building!