unhappy with oyster max brake

[2blessed]

I've been using my oyster max for nearly 3 months and am becoming really frustrated with the braking system. It usually happens when I am on a bus. I engage the brake but the pushchair still rolls. DP reckons its because it is a one wheel braking system. I previously had a vista and it never did this in the same circumstances. Do you think this is just the way it is or do I have grounds for a refund?

[Tiggywunkle]

Have you phoned up your retailer or Babystyle up and had a chat? I would ask them for some advice TBH. They may know why this is happening. The Oyster Max is a really good pushchair. It may be something simple needed to fix it.