you reached max limit of 3 .. hence it is not happening.. it is not because of downgrade..
you can only have 3 cards.. for you to have neo rupa card, you need to close one of the cards.. you need to tell the whole story at the beginning.
@Anon1 , sorry can't help you because I dont spend too much time on 🪓 cards. In myview it is not worth spending any time on knowing 🪓's policies. all the best .. bye
Ask if you have Neo Rupay LTF preapproved offer. If so, avail it and then close IOCL one.