This is a tricky situation and just highlights the worthless ness of the CSA, in this case there is a claim each way, yet they are quick to take on the one where it has proven easy to get details yet don't wish to put the work into the other where details have been less forthcoming.
Not knowing the full details I would say that there is a protected income amount that the CSA can not touch. Now if the figure of £160 is based upon net weekly earnings and the reason your friend becomes homeless is down to the fact that the rest of income is for paying other bills and loans or the such then unfortunately the CSA will not look fairly upon the impact their bill has upon the person.
In the first I would urge your friend to highlight the inequalities and get the CSA to chase the ex for the monies due for the 7yo. Unfortunately it is going to mean a lot of badgering, not helped by the fact that the calls to CSA can often be lengthy and cost at the standard rate charge (unless they or even a friend has free calls to 0845 numbers!!). Also in some reassurance is that when the details of the ex are finally sorted the CSA will be chasing back payment from the date of the first contact for a claim, so at some point there should something to show, but no guarantees on how long that may be. Just tell your friend to stick in there and support them however you can.
