Call them and see if you can work out a payment plan

Say you’re $100 behind on something, and the normal payment is $30. Maybe they’ll accept payment on the overdue amount over 4 months. So for the next 4 months, you send them $55(the normal $30 plus $25 catch-up payment.
Assuming that payment fits in your budget, it does 2 things. One, you’ll be caught up on that one in 4 months. Two, in the fifth month you’ll now have that extra $25 to throw at another bill. Do I hear a rolling snowball…? :-)