It appears the landlord, by virtue of the management company, is making a good faith effort to remedy the situation. If the landlord was not making a good faith effort to fix it, depending on what provisions are in your lease, you might be able to use the "repair and deduct" remedy.
If you unilaterally make a lower rental payment next month, you could be in breach of your lease and your landlord could serve you with a 3 day notice to pay or quit.
Please be advised that we have no attorney-client relationship and that this should not be considered legal advice. You should hire an attorney to ensure you follow the provisions in your lease and the applicable landlord/tenant statutes.