I've reproduced the behavior - try running "mwg-switch-repo 18.104.22.168" first from the command line. Should do the trick.
Worked also fine for me.
The command "mwg-switch.repo" was only working when starting from /opt/mwg/bin
mwg-switch-repo 22.214.171.124 followed by yum upgrade did the trick.
The repos have been corrected - all should work as documented now.