Should I pay two-month rent penalty in case of early termination of my tenancy?

Hi.

I am a tenant and gave notice to my landlord on 3rd July 2017.

The contract was for 12 months starting March 2017 but had the following provisions:

"The Parties agree that there may be instances where the Tenant shall need to terminate the lease early, and in accordance with current guidelines the Tenant will give a two-month notice and two-month rent penalty in the case of immediate vacation."

The landlord did not come to the pre-agreed date of vacating the premises on the 7th of September because I refused to pay him the two-month penalty, although I had already given him over 2 months notice.

He is saying I have to pay him the additional 2 months even though I read it as only payable if I vacated immediately.