Sometimes it can be a defect in the blank. Honestly would have to see a picture of the break to really determine. Could have been a stress fracture from shipping, store mishandling, etc... so many possibilities. Depending on the manufacturer if it is a defect the will usually replace the rod with a minimal fee of less then 30-50 dollars depending on the company.
Check with the website of the rod manufacturer for details on repairs.
Sorry to hear about your mishap.
Regards,
Waders