Actually, it was not the belts fault, it was the installer's fault. The nut that holds the face plate pulley came loose, and then all kind of things went bad, and it pulverized an almost new OEM belt, with some other damage...
I hope this is not what happened to yours? I had the belt changed at 13,000 miles and the original OEM belt did not really need it then. It had inside the "teeth" cracks in the rubber, more age related (7+ years), but no abnormal wear. Kymco gives the 250cc OEM belt 16,000 miles before changing.
I am a bit confused about your situation, is this is already your second belt, and somebody else changed it for you? How many miles ago? If it IS the second belt, how many miles did you put on your first belt?