The advice I was given a few years ago by someone who used to work for the CSA was, if you ever have issues with them, to ask to make a complaint about the maladministration of my account
I had trouble getting them to act on my account to collect the 1000's owed by my ex
Within 6 months of making that 'official' call, I had 1000's in my bank account that was owed to me because the CSA had at long last implemented the tools they have to their hand to use, such as going to court, seizure of goods by sending in baliffs if parties didn't show up in court and more
I'm not sure £44.50 per week is enough for even one child, at least you have been paying, even if it has been under some duress in the past
Good luck