Got a full time job after being with them for abou...

Got a full time job after being with them for about 15 weeks but during that time they just messed me about, not paying me the right amount some weeks or forgetting to pay overtime. And now weeks after I have left they are accusing me of keeping safety boots from them, when I had my own and are trying to get me to change this comment. I have removed the things that were untrue from this but have kept what is true and I am keeping the texts from them just in case, useless agency