If you're unsure as to whether you may have one of their faulty cases, send them an e-mail with details of the date of purchase and the supplier.
Tim Turnbull the Chief Executive of Aquapac International Limited, London contributed to the Forum thread below to say anyone could e-mail him about this email@example.com
If they believe your case might be affected, they'll send a postage-paid envelope to return the case for checking. There's a Forum discussion of this here.
Damn good customer service I say.