Go back and politely challenge it with the shop if you are unhappy, if they say it’s impact damage and you genuinely* recall no impact of any noticeable** magnitude then, and it broke then it is neither:
– of satisfactory quality and
– fit for purpose
And the onus is on them to prove that it was. If it cannot survive normal use*** then it’s hard to prove it fits the above. No need to go in all guns blazing, but an honest but firm discussion to start with.
Remember that your relationship is with the retailer, not the manufacturer, although complicated in this case if bought from a concept store, although they ARE different entities.
Having said all that I predict problems if they think it was impact damage****, are there any visible signs of impact to the paint/finish or is it ‘just’ a crack?
*
**
***
^ they will be the argument points, be prepared for them.
**** – Ask them to explain and define what kind of impact they would have expected to cause such damage.
– If they answer with something well in excess of what it has experienced then explain that hasn’t happened, you disagree with their assessment and want more proof.
– If they answer with something very trivial then it lends support to you fit-for-purpose/normal use argument for replacement under wartanty or at least goodwill gesture.