HDB did not repair toilet ceiling leak

[rxhxn]

I'm really angry with HDB. Toilet ceiling leak was reported in 30th Nov 09 but till now 23 Jan10, the leak was not repaired.Hdb officer also did not bother to reply my email.its only when i went down to the central office and leave voice mail then he called me back to inform that he had sent letter to upstairs neighbour.When i approached my upstairs neighbour, they are waiting for officer action, so both waiting for each other. Thinking to engage lawyer to sue them. Any better option, anyone suggestion?