We've registered makepositive to be used as custom domain name on 24th December, we received the email that the domain is ready for testing on the same day, however we were unable to login using the url for "makepositive.my.salesforce.com" we received. More so, the domain name "makepositive.my.salesforce.com" is not listed in the My Domain screen, nor is the option to login using this to deploy this to all users.
Can you please help us out with this.

We want to enable My Domain for our Live org. we already have some existing sites working and we’ve implemented My Domain in our full copy  Sandbox, the urls for existing sites are not changed. Please let us know a possible reason for this and if implementing My Domain impact the existing Site urls in any manner.

Thanks