I have minecraft as premium and i had no issues while playing it like 2-3 years ago. And now i've tried to log in with my E-mail and normal username but it still denies it and says "This Mojang account has no purchased copies of minecraft attached" or "Invalid credentials. Invalid username or password." I've tried to login at least like 50 times, and im pretty sure that i'm not doing anything wrong so i thought that i might get some help. Why is this happening ?