UBI, by itself, doesn't even eliminate poverty: consider the simple case of where the payments on your debts equal your UBI. You are now exactly as badly off as someone with no debts and no income.
The same is true for people who have medical needs in excess of that covered by UBI, but no (or insufficient) health insurance.
I suppose it depends on your country, but in the U.S. your income would never be garnished to the point that you couldn't afford basic living expenses. Most UBI schemes pay below the poverty level, which means it's unlikely your UBI payments would ever be taken to pay down debt.
IOW, you're absolutely better off with UBI and massive debt than you are with no UBI and no debt.
Here in Sweden there is a rule that dictate that local government must provide housing, food, healthcare and education to all people officially living in their region. This rule sits above any potential conditions that they want to impose.
This does not mean workers do not get exploited, or that people won't take jobs they don't want to do in order to escape bare minimum of living.