I write from NSW and assume consumer law is similar in the Sunniest State of the Nation.
There are a couple of different ways of looking at this problem.
1. Take the matter to Fair Trading and accuse the landlord of deceptive conduct. He/she advertised facilities available inclusive in the rent which have never been provided. I don’t know what the penalty for that is. That’s something for you to look into and list in your claim for damages; or
2. Estimate the cost you would otherwise need to pay a gym to use similar facilities as often as you would like. Let’s say $40pw as an example.
(a) Go to Fair Trading and sue for $40 x number of weeks you have signed a lease. Seek an order for that amount to be paid to you; also seek compensation for the time and money it would take to travel to a gym, multiple times a week for the duration of the lease, say $25 pw;
(b) So if you lease is 52 weeks long, seek an order for ($40+$25) x 52 = $3,380; and (c) Make clear in your submission that you are a reasonable person and even offered to pay to use the gym ie PAY AGAIN (because you already paid for the gym in your rent), but your offer was refused.
After all:
(1) But for the advertised inclusive gym facilities you would NOT have signed a lease at the rent offered; OR
(2) Had you known there were no gym facilities, assuming you liked the building, then you would have only agreed to a lower rent than the advertised rent. Taking into consideration 2(b) above, with no gym facilities you would have considered signing a lease if the rent offered was at least $65 less than what you’re now paying. Or possibly NEVER signed a lease with that landlord.
Note: the internal affairs of the building i.e the Owners’ Corp’s (“OC”) decisions on who can or cannot use the gym and any court matters relating to that are:
(a) Out of your control;
(b) Between a landlord and the OC or between multiple owners and the OC; and
(c) Frankly, are irrelevant to your dispute. After all, you contracted with one landlord and not the OC. Your landlord has not delivered what he has charged you for, week in week out. For that he needs to compensate you.