Spitz very unproffesional

I recently bought Carvella flip flops at Spitz and this was in july. I wore them a few times and they are ripping/torn even the words on the shoes are coming off. I went to the shop yesterday at Spitz promenade to possibly for an exchange to get another pair, because i have worn them a few times but they are damaged. The sales associate there told me i cant return the shoe as it is not completely damaged, so i must just wear it until its completely damaged. I am soo dissapointed and angry because when i buy carvella, i buy a brand that i can trust and when i go into a spitz shop i expect quality first of all, and exceptional service. A returns policy is in your invoice and this is obviously a factory fault, why should i continue to wear an ugly shoe. I do have other flip flops from other brands, even cheaper brands and i still continue to wear them they are perfect. I am absolutely dissapointed