Redirect to new (non-wordpress) website on another domain

Hye,

A customer of my created a free wordpress blog.
With free hosting on a domain something like: “https://mySite.wordpress.com/”.

Now the customer has a new (non-wordpress) website on another domain (like: https://www.mySite.com).

I cant found out how to redirect the wordpress to the new domain.

-I cant do a 301 redirect with htaccess because there is no ftp account available

Someone a solution?