Crocs India — Exchange for proper size

I have placed my order on your website on 19/11/2023 with order no[protected] . and i received my order on 25/11/2023. after getting delivered my order i came to know that i need one size down for me to fit the best .Since than im trying to return and get proper sized clogs for me, but i failed to contact you people through your customer service number and tried my other ways . so, please consider this and get me the proper sized clogs. and Please tell me the procedure to return and get back the proper size or refund.