Flipkart — Wrong item given with incorrect Serial number

Hello sir, i recently bought honor magic watch 2 on 27th july 2021 with order id order id 'od[protected]'. I received it on 29th of july 2021.
I was very happy with the product however while exploring it i noticed that i was unable to to use it with full potential as i was using any demo product. I contacted honor customer care and they asked for the bill however there was no serial number mentioned on the bill which is very necessary for warranty purposes. Hence customer care executive asked the serial number present int software of the watch (In settings — about — serial number). Whaen i provided, to my surprise i come to know that it doesn't matching with their systems. Hence, it is clear that seller has given me some different item. Hence, i raised the concern on the flipkart for the refund. However they are taking their time. If in doing so, timeline of return is passed which is 5th of august, then will my product will be eligible for return.
Please look into the matter do the needful so that i can get my refund as early as possible.