Ok, for that you need the Custom HTML field solution with tab substitutions. First edit all 3 tabs within CB > Tab Management and change their Position to "Not displayed on profile 1". Now create a Custom HTML field on a different or new tab and use the below substitutions to stack the contents of those 3 tabs into 1.
HTML:
Code:
[cb:usertab tab="TAB_1_ID_HERE" formatting="divs" /]
[cb:usertab tab="TAB_2_ID_HERE" formatting="divs" /]
[cb:usertab tab="TAB_3_ID_HERE" formatting="divs" /]
Show on Profile: Yes, 1 Line without Title
Show on Registration: No
Show on Profile Edit: No
Replace TAB_1_ID_HERE, TAB_2_ID_HERE, and TAB_3_ID_HERE with the actual IDs of those 3 tabs. You can find their IDs within CB > Tab Management on the far right under the ID column.