Over charging for his work

I had a trade from Rated People, l feel a fool and very upset on how much her changed me for a job. He also took money for building materials before he stated the job. He did not give me a bill on how much he spent.He had half the money first than the other half after the job. He wasn't happy when l told him how much l gave him before he started the job, he said that was building materials he lied about the price. Than said o yes you have money left. I wasn't sure what to do so l paid him.He was due to start another job for me. But l didn't want him again do l sent him feedback by text about him over charging me for the job. I didn't think l would hear from him again, but he came to give me a price to plaster board and plaster a kitchen ceiling £700.00. I just said l would speak to my husband. I got a few more quotes there price was under £300.00. How can this man do this to customers. I wouldn't like this to happen to anyone eles. Is know l have to move on from this but he is still on Rated People.