Dynamic Contact Form help

Hi all,
Wondered if anyone has any advice or suggestions?
I need a contact form that can have variable fields, in accordance to options selected. So for example, if someone selects lets say a product from a drop down list, the form will then display product specific options for the user to choose from. The options will be specific to the product, so depending on what product is chosen, will depend on what options open up..

I am not sure if a plugin that does this exists, can anyone help me?
Im sorry if this is the wrong forum for this question, I look forward to hearing from you..

Many thanks.