Porting landline

I see I am not the only person having this issue but I was promised that I could port my old number over to my new xfinity account. It was originally a comcast number. Well, I am all installed and after calling tech support (which I had a very difficult time understanding) he told me that I can't have my old number. I am about 12 miles from where I was when I got the other number so I haven't moved out of the area code or very far. What is up with this? I purposely asked about keeping the number when I signed up. Help!!