Moving from cpanel server to a new cpanel server DNS change?

Hi

I am using own nameservers as ns1.myadomain.com and ns2 on a cpanel server.

Now i move to another cpanel server and i have the same ns1 and ns2 and i edit them to the correct new ip's but i am still getting by ping the old ip's for ns1 and ns2 :(

What can i do for it?

Thanks