You have not managed the debt because you have missed some payments and only paid the minimum. If I was you, I would definitely live as though I was poor for a while, make it a real target to budget carefully, cut out luxuries, sell outgrown toys and clothes on ebay/facebook.
Look at your phones - do you need the tariff you are on? Amazing the amount of people who pay £40 or more on their phones! I use a decent android which cost less than £200 and a sim card which is under £10 a month. I don't watch movies on a train etc, so I don't need tons of data. Most of us don't.
Use cashback sites for switching and factor that into the cost. Do you have Sky? Switch to Now Tv. Same content way cheaper. Do you have Netflix, or any other paid subscriptions? Cancel them to add that amount monthly to your debt payment.
Set your heating timer low (I'm talking about18/19degrees) and with longer off periods in the day (that way you can boost it if very cold and you avoid heating an empty house when you're out). It's incredible how quickly you get used to a cooler environment. And have the children wear slippers/ jumpers/onesies, have a blanket by the sofa.
Think twice before you buy anything.
Buy big brands and you're paying for the marketing, not necessarily a better product.
Stick a handful of lentils in soups, stews, bolognese.
Meal plan - a 2 week rolling schedule works well.
Eg. week one with limited meat every other day or so:
Monday - jacket potatoes with beans/cheese/chili
Tuesday - Sausages and mash, peas/beans
Wed - Pasta night
Thu - Chili/curry night
Fri - Pizza treat night
Sat - Big brunch day - bacon, eggs, chips/hash, beans, tomato, etc
Sun - Roast day - chicken thighs/drumsticks are cheap and enjoyed by kids.
Make porridge every morning. Change the toppings around or have a fun choice - syrup, chocolate chips, sliced banana, party sprinkles etc. Much healthier, cheaper and lower in sugar than the kids' cereals.
What treat foods are you buying? Do the kids have crisps, cereal bars etc? Get into new habits like chopped up fruit (much more appealing to kids than a whole piece!), carrot/cucumber sticks and dips (hummous is cheap and easy to make), toast, homemade pancakes etc. Do you heaven forbid buy fizzy drinks regularly? Even squash is a habit that can be tailored out ("Oh they didn't have any x flavour left this week, sorry!")
If it seems too much to eliminate this kind of treats, keep for a special day - saturday movie night!