Capitec won't help

Ok, so I am trying to get a loan or credit card with capitec, however they are refusing to help me. I only have a telkom account on my name but that is not my responsibility due to the fact that people rented our house and racked up the debt. Now I need an urgent loan and capitec says I have a low credit score. How am I supposed to build a credit score and no one is willing to help me???