How do I get my outgoing calls to display my SIP call display phone number, not my user name / account number?

Question

Hi, whenever I call, people see my six digit user name / account number (e.g., assigned by my voip provider voip.ms) and not my phone number as entered in my caller ID, so a lot of people refuse my call thinking it is spam.

Is there a setting I should be changing or is this a bug?

Thanks,

Tom