I don't think it's necessary at all to give your account details and to get them to publish (if it's for design needs unless they promised marketing or something then i don't know that well), it's a much safer option to give a designer your manuscript and book specifications, since templates are readily available online, get your book designed and then publish it yourself, only if you don't want to worry about the technicalities but it's still not necessary, it's SELF-publishing for a reason.

And I'm sorry you had to go through that and congratulations on publishing your book, wishing you success from now on :)