Car rolls back on hill when handbrake is fully engaged?

Hi Team,

For some years now, I've noticed that my car tends to roll backwards when the handbrake is fully applied when parked uphill, as you can hear a "groan" brake noise as it rolls backwards slowly.

I have complained so many times to the dealer but sadly, they said the only thing they can do is just to adjust the handbrake cable to tighten the brakes, as the cable and pads are in perfect condition.

Given that I live uphill, it is getting scarier as I've noticed that the handbrake itself seems to get worse by the month.

Note: The i20 I have uses rear brake pads and not shoes.

Grateful for any pointers and suggestions that may help fix the problem.