Investigation to credibilty backgroud of the supplier in China

Hello,

My name is ***** I live in Great Britain. I am going to buy a machine  China. However, I do not want to be a victim of fraud or buy something that is not as described. Do you help in making transactions, in this case a company  China  a private person  the UK. I would like to find out to what extent the company is legal  whether its services  products are consistent with the description  photographs they present. I would like to sign a contract with them which will be legal. In advance, I would like to know what your costs are for this type of service.

Best regards