How can i have 2 tax numbers

I have been garnished by Sars for a tax number that doesn't even belong to me.I have 2 tax numbers,when I give them my ID number ;they say my profile shows that I don't owe but on the other hand ,they are deducting 2100 every month from my pay saying I owe them 38k 😪😪very disappointed because no 1 wants to help me