Ex lying about amount he spends in contact costs

[skye33]

Hi has anyone had any experience in " contact costs " finally after a year received the right amount of maintenance from my ex through the CMS after a long battle and now received a letter saying my ex requesting to have the amount he pays reduced because of travel costs he incurs. What I'm annoyed about is that he is blatantly lying about the amount he has to pay in petrol. I drive half way each time and more often i drive closer so his journey even shorter. I have all the times he driven documented so can say that it is no where near the amount he claims it is. My question is does this count as proof as surely he ll just say different and lie again to CMS. Seems he s just plucked a figure out of thin air and put this down. Anyone had any experience of this ? I do live 110 miles from him now but that's because he stayed in our family home when we split ( not married name my name not on mortgage ) and I couldn't afford to stay living in south so had to relocate. It was due to necessity rather than I wanted to. I'm struggling to pay the petrol as it is as obviously it costs me each time I drive as well. He also has a fuel card through his job so doesn't even pay for fuel although it is capped it's very generous and I know he abuses it. Any advice please ?