There are two types of Court in England: Criminal courts where you are tried for offences against the state, and civil courts who hear disputes between individuals. If the police and the CPS don't think there is sufficient evidence to bring criminal charges, they won't act.
If someone has caused you a loss, either deliberately or negligently, you can sue them through the civil courts. If we're talking about less than £5,000, the County Court is the best place to start. If you want to go ahead, go to your nearest County Court and take out a summons. (There's a charge) That involves completing a long form that lets you put your side of the case. It then gets sent to the other side who can either pay up or dispute it. If you get to that stage and you want to move on to a Court hearing, it's best to get a solicitor - and that's when it starts to get expensive.