Hobby Shower Tray

We bought a new Hobby Siesta in May and during a Christmas Trip to Spain the floor of the shower has split.  You can feel that the majority of the floor is well supported and ridged but where it has split there is no support under the tray - the thin plastic tray supports all your weight.  The dealer is most unhelpful advising me to contact hobby, hobby have said go to the dealer.  I am persisting with Hobby, has anyone out there had this problem? or can you advise on how to sort this out.  It really must be a warrenty issue due to the unsupported tray.  We are 2.5hrs away from Hobby depot.  Thanks xx