We have multiple ways to do the same.
You may be able to go into /etc/yum.repos.d/ and remove the file corresponding to the repository.
You can also try to remove the repo and add with yum-config-manager
yum-config-manager --disable repository
yum-config-manager --add-repo http://www.example.com/example.repo
You can temporarily remove/disable a yum repo by adding the --disablerepo=(repo name) to your yum line.
yum --disablerepo=some-repository install some-package