In the attached screenchot of that thread, the unique key is both person and number but you have defined only person as the unique key..I have not worked on the problem yet but I think when you define the the person as unique key only then while uploading the numbers it will replace the previous uploaded number rather than adding the new..
Why? because we have defined that person name should not be repeated or duplicate,if found so then replace the data with new one..
When we define both numbers and person as the unique key then while uploading first it will upload the first number against the telephone type then second time while uploading the next, the number and person together are different than the previous data so it will allow to upload the next number and so on..
Also try to make telephone type a unique key along with number and person..
One more suggestion, taking person email or employee ID as a reference item is a better option than person name because there make be duplicacy in the person name but not in the person email or employee id..
Hope this helps..kindly revert if not found the desired solution.