Generally speaking, there are 2 kinds of fraud - criminal fraud and civil fraud. Criminal fraud is prosecuted by the Government and civil fraud is prosecuted by the victim.
This case is an example of civil fraud.
Why the firm has a case in this case? The reason is simple - although not required, IVA is usually a step before bankruptcy. When you requested IVA service, you represented yourself as you choose IVA and allowed the firm to work for you. However, you chose bankruptcy instead.
Since you have misrepresented your intention to the firm, the firm can legally go after you for the cost of service.