Spice Jet Airlines — Extra seat return

This to inform you that I Ratan kanjilal purchased two tickets from skyscanner vide PNR no QBME8Z dt 28/06/22 from Mumbai to Kolkata by paying Rs 15895/- for your flight no SG 467.
Suddenly I received one SMS saying that I have to pay an additional Rs 4857/- for an extra seat before issuing the boarding card.
I was surprised to know why I should pay extra this amount.However due to urgency I had paid the same amount for getting two no of boarding cards, 6A and 6B respectively.
Please note approaching the checkin counter in Mumbai, your executives were also surprised and could not alloted extra seat. That would mean you have taken an extra amount unnecessarily harassing me.
Requesting you please refund the amount of Rs 4857/- taken for 3rd seat in my account.