Bad Customer Service

On the 28th of December my sister bought a dress on sale@ Zara Cresta Mall. She was not given a till slip but Zara claims she was given a slip. On the 29th she brought back the dress for exchange as it was big using bank proof of payment. Zara refused to assist her. I then send a complain to customer service and this their response "We deeply regret that we cannot help you on this occasion:

On the same token we provided the bank proof but still not assistance. Thoko ( Manager) from Zara Cresta Mall went extra to check the footage and she confirmed that my sister was there but still she couldn't assist and referred me to HO

Zara HO responded saying" The original purchase receipt and if used, the credit card and charge slip will be required. So why she wasn't assisted when she was in store the following day.

I would like to express my disappointment from Zara unsatisfactory level of service. I have expected much more from a prestigious and reputed company of your standard.

Zara must look into this matter and provide positive feedback.