Ex gets more in benefits than I make working

I receive, (well sometimes!), £10 fortnightly from my ex-partner. Despite my ex getting more in benefits than i have coming in. I had not received it for a few months and lost out on over £100 as they failed to sort it out despite assurances i would get this money, i will not be holding my breath. It has now been stopped, (again), and now i have to go through the hassle of complaining,waiting and losing more money as it does not get backdated. It is already an insult receiving a paltry £5 a week.

What i want to know is how my ex can get away with paying this when she makes more in benefits than what i can make in a 40 hour working week. The only reason i pursue it, is the fact i know my ex grudges paying it, (certainly not for fiancial gain). This whole system is a farce at the least.