I'm not happy with telkom at all I need that number back I'm a student

I've been using my *** number since 2021 and I lost my phone with the sim card inside so when I went to the telkom branch they told me that they can't help me because I didn't register my number under my ID number but I've been using that sim card for more then 2 years I've been buying airtime and data with that sim card and I even registered my important stuff with the same number and I can't get to use it again because its not registered why didn't they block that number before I even used it, I need the number back because some accounts can't help me in changing the number like my nsfas account they tell me to go to telkom which I also don't get help from cause they keep telling me that the number ain't registered but I've been using it for years I need help getting that number back because I have to access my nsfas account to get my money.