I don’t understand the issue and its relation to Kodi.
We changed the way accounts work to simplify things when we add more services.
You can email or PM me and let me know which email account you want associated with your old account. Then you can create an account under My OSMC with the same email and the posts will be linked.
For the web shop you can use a different account – you’ll just need to sign out when swapping between them.