Essentially, allow people to pre-commit to paying for a specific expense to a private organization which has to provide that service. They can opt out later on, but only before their next basic income check.
Also, I think there should be some sort of auto-enrollment system. So if you're found homeless, having blown all your BI check on booze, you'd be automatically enrolled in the top housing provider.
"Top" is relative, you can be at least given the choice of provider, but I am absolutely certain in a UBI scenario offering your UBI for simple living provided for you would be a huge industry, and would also account for anyone who cannot manage money like OP says just fine.
Essentially, allow people to pre-commit to paying for a specific expense to a private organization which has to provide that service. They can opt out later on, but only before their next basic income check.
Also, I think there should be some sort of auto-enrollment system. So if you're found homeless, having blown all your BI check on booze, you'd be automatically enrolled in the top housing provider.