Stithing torn

I recently purchased a pair of Puma running shoes from Total Sorts River Square, after wearing the shoes not more than 20 times the stitching tore on both shoes. I don't even use the shoes for running and only wear them casually. I can forward pictures if need be. I have 2 other pairs of Puma with no problems what so ever. Maybe it is this particular range that have the problem. I would like some feedback if possible. I think I paid R1200 for them and expect a bit better performance from this brand as it is one of the best out there.