Is this not against medium terms and conditions? It is only possible to upload up to 5,000 email address and medium terms state email address cannot be bought from any third party. I was thinking of doing this but what I read below put me off.

This is what I read:-

" Import your subscribers
Writers can import a list of the subscribers you collect from elsewhere. You can only import by agreeing to follow our Email Import Terms of Use, including important requirements that apply to your use of the import tool. For example, you agree to only upload subscribers who've signed up to receive emails directly from you, and not have been obtained from a third party."