Edgars selling defective shoes and not seeing sale on system

I bought a pair of heels at Edgars. They fit my daughter when we left the store. She didn’t even wear it at the event that she was supposed to wear it at. She just walked around the house perfecting her walk. The decorations on the shoes started falling off and the heel was a bit loose.

I returned it for an exchange and they said they couldn’t find the purchase on the system. I obviously threw the slip away cause the shoe fit and I wasn’t aware they sell defective shoes. The purchase was done through Pay Just Now and had the receipt but still I had to go back with the shoe cause they couldn’t find it on their system.

What was strange was the lady telling me I should keeps receipts, why would I keep receipts for shoes that fit?

This was at Hemmingways in East London. I was told to come back on a day that’s not busy, I’m not sure how I should know which days are busy or not.