Showing demand since last more than four months even after its payment

I received a demand of ₹600 on 17/11/21 which I paid on 17/11/21 itself with minor code 400. The response to outstanding demand was submitted with details of challan on 28/12/21. The paid tax challan is also properly showing in my 26AS. But still even after lapse of more than 4 months after payment of demand and submission of reply, it is still showing outstanding on my efiling portal. Lodged grievance also on efiling portal three months back but no response and action by Income Tax deptt. What to do.