Amazon India — Refusing to provide refund

I bought a watch from Amazon.in. The watch had a 30 day return policy and was eligible for a full refund if returned within that window. I have returned the watch, but now Amazon India refuses to process a refund stating that the return that they received was different from the product that I ordered. Everytime I call the customer support number, they simply say the investigation team has decided this and we have no way of getting in touch with the investigation team.