We see no evidence of sand in the detailed photos you have supplied which would be required as per instructions.
Clay is an incredibly reliable material, used for 1000's of years and the products invariably do not come with faults. Likewise 1000's of items are sold every year without issue. The only issues that arise are from delivery breakages, thermic shock from over firing, and/or misuse. Clay chimineas do require careful use, and seasoning with numerous small fires to bake the clay solid. Likewise throwing logs in hastily, or through the flute will also cause damage.
It looks like very clear Thermic Shock / Misuse which is a usage issue and not covered for replacement sadly.
