My ex moved in with a woman with 2 children, he instantly called cms to have his rates reduced. He only lived there for 2 months and I tried to report they’d split up as soon as I heard but for 5 months he’s gotten away with paying the reduced maintenance rate. I called this morning to see why my reports of his where abouts keep getting rejected instantly and they’ve now put it through. I’ve asked if I’d be back dated and they said only from this phone call onwards. I don’t know if I’m being unreasonable but I don’t understand how it’s up to me to declare his marital status, address or whatever in order to receive the correct amount of money. He’s always been sneaky and has a huge amount owed. Should I write a formal letter? Or is it a loose end? Thank you in advance