On the subject of phones talk to the companies involved. I'm with EE and for every year you are with them you get loyalty points / they might call it something else.
The points can become a discount so I currently pay £3.28 (It has just gone up from £3) a month for unlimited calls, unlimited texts and 40GB data.
This is a SIM only deal but that means I can choose to buy a phone from anywhere.
Also talk to the credit card companies, they are all different but they all have an obligation to help. They can freeze interest, or close the account - yes it has an impact on your credit score but your score is probably quite bad already.
I had a card with Vanquis, when I had a problem paying I called them and explained the situation, I'm now paying that card off at £1 per month with no interest.
The CAB can be good, even just finding info on their web site.
Instead of thinking, "We have to pay X on CC" change it around, do a complete income and outgoing with everything from a coffee or a 10p dropped in a charity tin to wear and tear on cars, to birthday presents, everything.
Then what you have left over is what you can spend on debt.