Hi!
First of all, you should take out all the mods, because they can cause all these issues and if that's the problem, It's the creator who should fix it.
If that doesn't work, you can still use the cheat “sims.modify_funds <amount>”, instead of "amount" you have to write the amount of money you want to add to your household, so they can pay that bill.
If that cheat does not work, use the testingcheats true and then type money 9999999
Good luck!
Update: Now I have seen this issue a couple times more. It seem to have no solution, so maybe you should save the lot and the family to the Gallery and then put them back in a new game. It seems to be no other solution ☹️
