Unfortunately my advice is purely my own idea and interpretation as its the way oneself would attempt to process the scam game they are playing with you. Its in no way legal advise.
1. Apply for extreme hardship.
2. Dispute their decisions.
3. Continue disputing every decision against you.
To my knowledge, you entered into their contract once you begun a payment plan.
Continue to research your rights. Understand why the Taxation commissioner has no authority.