Myntra.com — myntra does not take back their product giving reason not matching serial number

Address: 127045

I order a jacket for my father, size fit issue so i make a return request same dday when the product is delivered.. But the agent came for return and said that the serial no is not matched.. I contact customer care they assure me to solve it very soon.. I again make a return request but the agent refused to take it back because the serial no is not match.. Rather all the tags and bill is same.. Product is unused... How bad service they have... Behave like a fraud... Soo bad.. Plzz help me to sove it...