What happens next?

How to respond to a retaliatory landlord
Collect and keep any evidence of the landlord's retaliation.
As soon as the landlord begins any retaliatory action, you need to collect evidence of it. You may be able to resolve your dispute with the landlord without going to court, but in case the matter does go to court, you will need evidence.
Keep copies of any letters or notices that the landlord sends you that you believe show the retaliatory action. Take photos of any negative living conditions that are the source of the problem.