RHES for the s390x platform

Hi,

New to this. I have been trying, unsuccessfully, to get a copy of RHES,
to run on my IBM z9 mainframe.

I have signed up for the 30 day evaluation, but this system does not
appear as an option to download.

I opened a support question, they said check with sales. I sent an email
to sales, they don't seem to care, since they have never returned my
email. 
Does anyone know how to get a copy, so that I can evaluate it.

Thanks
Tim