Hush Puppies — severe pain in feet after using the product

I had purchased sandle UK size 4 with Aricle Code [protected] of Hush Puppies from Bata, Vivacity, Unit No. SF-8, 2nd flr, Voltas Compound, Pokharan Road No. 2, Thane, Maharashtra, India by Invoice No.CM[protected]dated 13.11.2018. I could not use them for next four months as I wanted to use them in the month of July. Since the product is purpose of all season use I purchased it clearly getting assurance from the sales girl that it will not give any trouble. I started using them since last 15 days. But after using them I am having severe pain in my feet to the extent that I am on pain killer tablets. Now I cannot use them inspite of spending almost 4000/- on the product. I will, therefore, like to get them exchanged with other product