Trainers split after one month.

I bought a pair of Nike Circuit Trainers II from Limited Edition shoe store in Somerset Mall on the 14 February for my son for school. On the 13 March 2015 (one month), both shoes had split on the seam behind the little toe. I took the shoes, with the box and the receipt back to Limited Addition, and they told me they have to send the trainers back to Nike to be evaluated. I told them that my son doesn't have another pair of shoes for school, so I can't send them back, and why must it be evaluated, a ****** can see that a R800.00 pair of Nikes shouldn't split after one month. I asked if the Nike rep could come and see the trainers here, and they said the rep doesn't come out, very surprising! This sounds like the normal lies some shop assistants tell. I would like to know from Nike if this is how they operate, and if not, then why do they supply shops/outlets that do. Please advise.