Hosting Mella — I have submitted new nameserver request but after 24 hours it not updates

I have submitted nameserver change request on hosting mella website before 3 day ago. after submitted nameserver request they are showing that we are taking 24 hour for nameserver change in wesbite. and then I created ticket in their website but no reply. and then when I message on customer support whatsapp number ([protected]) after 2 day of nameserver request submitted through website.. i had sent message on morning they are replying me after many messages in night time . and then again they are asking me for new nameserver details I provided again..i am still waiting after 4 day of my first request submitted. they are not giving any proper reply or solution. my ticket no 378895