Adding a 3rd line to my account?

I’d started an account for one line, with new phone earlier in the year then added another with a new phone on Black Friday for another family member. The next day I decided to order another SIM card to switch my phone from another carrier. 
currently my account shows the two new phones/lines on it, how do I add the third one (with my transferred number)? 
when I log into the Koodo change my number link it only shows the first 2 new phones/numbers as options to work with.