Clarks — No one picks the customer service call

Address:	Mumbai City, Maharashtra, 400086
Website:	www.clarks.in

I purchased 5items from the clarks website on 10th august under order number is -4529403 and delivered on 13th august. The size of 2 shoe pairs are big so I want them to be exchanged. I tried calling the customer service number [protected] many times but no answer. Also I e-mailed to the website address but still no response. I don't know how to approach them.
Thanks
Rishi Gupta
[protected]@yahoo.com
Contact number-[protected]