Could you give more information? Based on the facts as you describe them, you are better advised not to enter litigation as a win for you, though probable, is worth far less than the amount you could be caught for if you lose.
If I were in your shoes I would get talking to your other neighbours, to explain what happened. The hefty sum that you and everybody else pays each year is collected to deal with the very type of maintenance issue that you paid to fix out of your own pocket. Your neighbours should be sympathetic towards you at the very least because you solved the problem for them too. I would ask for a meeting with the agent and put the case to him or her with the backing of fellow residents. If the agent does not play ball, I would threaten to sack him / her.
Another route you might try is by referring the matter to the consumer rights organisation. You paid for a service and did not get it.