Myntra.com — can not exchange my product after collecting insider points

I bought a shirt as a gift for a wedding, but the shirt didn't fit and need one size bigger but by mistake, I claimed the insider point for that and now can't even exchange the shirt. I liked the shirt just want the bigger size so I contacted the customer care for the help to anyhow if they allow the exchange but they said there is no option.

If by mistake someone claims the points there should be an option to undo that or by talking with customer care can resolve that but they just said it can't be done. When those points are virtual and they know how much points are collected for they should have a way to retract that and offer the exchange.

My order no:[protected]-6139101