backup MX forwarding

[http://dummy.us.eu.org/robert (Robert)]

To: http://www.zoneedit.com/~sales

I would like to have backup mail forwarding for a free sub-domain that I
signed up for.

The sub-domain (http://dummy.us.eu.org) works fine, but, because I don't
own the main domain no-ip.com , I cannot change the nameservers and
therefore doesn't currently work with zoneedit.com .

Because I've already gone through the trouble of making everything work
with dummy.us.eu.org , I'd rather buy a service to solve my problem of
having a backup mail forwarding service rather than buying a domain and
making everything work with that.  (Not to mention that I'd actually have
to think up a name!)

I understand from your web pages that if I buy services from you, I do not
need to have the ability to change the name servers to get the mail
forwarding and other stuff.