I am having this same issue with the new line that I just added to my account. I went in this evening and changed my Share Name ID on My Account. Hopefully this resolves the issue, I did contact Customer Support via chat this evening, and they told me this typically happens when someone else had the number before you but clears up once it is added to your account within 24-48 hours.
I hope this helps with your situation, it seems that are situations are very similar with regards to the issue we're having with someone else's name showing up when we make a call to someone else, even on a land line with my issue.
I will keep you posted and will update if what I did this evening indeed fixed this problem.