I am getting this error when I try to apt-get update

Reading package lists... Error!
W: An error occurred during the signature verification. The repository is
not updated and the previous index files will be used. GPG error:
http://apt.simplexsolutionsinc.com wheezy InRelease: Clearsigned file isn't
valid, got 'NODATA' (does the network require authentication?)

W: Failed to fetch
http://apt.simplexsolutionsinc.com/repository/dists/wheezy/InRelease

W: Some index files failed to download. They have been ignored, or old ones
used instead.
E: Encountered a section with no Package: header
E: Problem with MergeList
/var/lib/apt/lists/apt.simplexsolutionsinc.com_repository_dists_wheezy_main_i18n_Translation-en
E: The package lists or status file could not be parsed or opened.

When I try to do an upgrade or install I get

Reading package lists... Error!
E: Encountered a section with no Package: header
E: Problem with MergeList
/var/lib/apt/lists/apt.simplexsolutionsinc.com_repository_dists_wheezy_main_i18n_Translation-en
E: The package lists or status file could not be parsed or opened.

I emailed the support folks at simplexsolutionsinc.com (the provider of my
VPN) to see if they can fix the errors at their end.

I assume I could uninstall the VPN from simplex solutions and remove the
ppa from apt, do the upgrade and install the software I need, and then
reinstall the VPN.

Is there another way for me to move forward and do an upgrade and some
installs without removing the VPN software?

Thanks!

Mark