Hello, I am happy to assist you today.
You are absolutely right here in how you are handling this, except that it is probably time to file something with the court.
You are entitled to hear regardless of your lease, and if your lease says AC too then you are entitled to that too.
You are not only able to withhold your rent, but you may also get a portion of your rent back from past months that you have paid without AC and heat.
I would file an action in the landlord/tenant or small claims court in your county, and ask the judge for a portion of your rent back (maybe half or whatever you think is reasonable), for all the months you have paid, ask the court to declare that you do not have to pay any further rent until the heat and ac are fixed, and ask for money for any other damages that you have, like any heaters or acs you have purchased, or any other incidental damages, like taking time off work to deal with this, etc.
Your landlord should not get a dime until your heat is fixed.
Let me know if you have any questions.