create a separate account with their own different email address and then can add only 1 extra email?

Or we can just have 1 account and have 10 inboxes?

I ran into a situation with you guys where you guys will not let us delete an email if we don't need that anymore and I had to refund because the guy in the support asked me since he said that I can not change any emails...

So, If I am correct, is that right? What if we don't have that email in the future and we need to replace any email, then what happens?

Can you please clarify in simple English and details?

Thanks.