I bought a 2013 SX4 SZ5 petrol 1.6l recently from a dealer that has its own garage. They gave us a three month warranty. The handbrake wouldn't hold on our steep hill. I took it back and they adjusted it so that the lever is now at a better angle and easier to apply fully but it's still not holding on steep slopes. Is this a common problem? They said this kind of brake material is a bit spongy, and generally didn't seem to take it very seriously. I'm now wondering what should be done so that I can take it back to the dealer and ask them to fix it. It's only done 26,000 miles.