I hope you did not send them the entire contents of the product that you believe caused your problem. If you did I think it will be difficult if not impossible to establish that the product caused the problem with the dash.

You are going to have to establish, i.e., prove your case. To do this I would start by having the product chemically analyzed and try and find out if there was some chemical in there that would damage your dash.

I think it will be quite expensive to establish the connection between the product and the damage to the dash without the use of experts to establish the connection. This is not something a lay person a prove on their own.