Very bad quality sandals

The quality of the shoes/sandals are terrible. I purchased 3 pairs of beautiful sandals. I didn't use them often, its not a everyday shoes but after 3 months they started to open up on the sides. I kept it away and eventually decided to take the back to the store but was told that I had to have the original receipt to exchange the sandals. The sandals was in the original packaging and one could see it was hardly worn. Who keeps receipts of purchases for months. I didn't expect the sandals to open up, they expensive and I expected good quality for the price I paid. Now seems that I have to keep receipts for all my purchases no matter how small the purchase is????