If switching from ATT and Keeping Your Phone Number AND You Purchased Your Cell Phone thru ATT, You MUST:
FIRST, "UNLOCK your phone" thru ATT by visiting ATT Unlock Mobile. You will need your ATT account login AND the IMEI number from your phone (if using iphone: Settings - General - About, scroll to bottom). You must have paid the phone off and used that phone on ATT service for 6 mo prior to unlock.
THEN, Visible will need to contact ATT on your behalf to release your phone number to Visible for the service transfer. FOLLOW Prompts and Emails from Visible...
ACTIVATION Error Messages: Even AFTER confirmation email from Visible that my NUMBER had switched to Visible, but my SIM card would NOT activate... it took me 3 days to get thru on chat to discover that Visible does NOT request Unlock of the "transfer PHONE". It Must be done online with ATT. My error message was ACTIVATION REQUIRED, Unable to Read SIM Card... Visible only requests Unlock of the "Phone NUMBER".