Basic income is not going to prevent people from taking on unsustainable debts.
Arguably it's less likely to do so than a conventional bureaucratic, means-tested system, since (i) such systems usually directly subsidise things people tend to get into debt for (housing, education/training, and medical care) and have a more flexible, living-costs-related approach to the size of the subsidies on offer and (ii) predatory lenders can chase the indebted far more aggressively when armed with the knowledge their target has a cash income of at least $xx per month and therefore could easily make the payments if they stopped paying for their house, food and health insurance...
Arguably it's less likely to do so than a conventional bureaucratic, means-tested system, since (i) such systems usually directly subsidise things people tend to get into debt for (housing, education/training, and medical care) and have a more flexible, living-costs-related approach to the size of the subsidies on offer and (ii) predatory lenders can chase the indebted far more aggressively when armed with the knowledge their target has a cash income of at least $xx per month and therefore could easily make the payments if they stopped paying for their house, food and health insurance...