Welcome!
Since you deactivated the account and changed the nameservers to your new host, that’s all you have to do.
You are getting redirected because your computer does not know you changed hosts, and since you removed the domain from InfininityFree, we don’t have a website to show visitors.
You can fix this by clearing your DNS cache (Your users, if you have any, will have to do this as well). This is an internet thing, not an InfinityFree thing, and you can learn more below.
Tip for the future: Leave your old website on your old host active for 3 days before you delete it