House problem

[pico]

We are having a problem with our builder and the APCHQ (Quebec new house guarantee organization)... The exterior water tap makes a loud noise (vibration caused by water pressure and making the pipes "hitting" each other as they are probably not secured properly) when we turn it on. We have asked the builder to come and fix the problem, but because our basement ceiling is already done, they are unwilling to investigate the problem further, they simply told us to open to the max the water tap whenever we use it. After several calls, they finally came and replaced a piece for the water faucet (the discovery of the problem was in september 2007, but the replacement only happened in june 2008). The problem didn't get fixed and the noise got louder... so, we finally brought in the APCHQ in August, 2008. But the organization told us that we have made our claim too late (the request has to be made within 6 months of the discovery of the problem), so they rejected our claim. Now we are debating whether we should go to arbitration... but this comes with a cost.. if we win the case, then the APCHQ has to pay all the fee. If we lose, we would have to pay half of the total fee. The total cost for a case would include the travel fees by the lawyers, lawyer fees, the location of a hearing room and also the cost of an expert (in our case, they could hire a plumber to investigate the problem). We only have another 2 and a half weeks to make our decision, any ideas?