Looking for plugin that can assign multiple roles upon registration?

Hi,
I have this problem on my site and have been searching for possible plugins to solve this but no luck yet.
So I have multiple plugins on my site that create multiple roles (e.g. vendor & instructor).
If somebody who already registered as a vendor now registers as an instructor, the LMS plugin will assign a new role to that user and remove the vendor role.
Installing ‘multiple roles’ plugins doesn’t help.
So I’m looking for a plugin that can either:
1. Assign multiple roles to a user upon registration
2. Disallow other plugins to remove roles from existing users and only allow them to add new roles.
Please give suggestions on possible solutions to this.
Thank you so much.

• This topic was modified 2 years, 4 months ago by Jan Dembowski. Reason: Moved to Fixing WordPress, this is not an Everything else WordPress topic