I bought laminate flooring and premium underpayment. I bought an extra roll of underpayment that was on sale because I planned to put laminate to another room after the current project was completed and wanted to take advantage of the sale. The installer saw there was extra underpayment and to my surprise used all the underpayment I purchased and installed my flooring with double underpayment! 300 sq feet area and used up 3 rolls of premium underlayment (200sq feet each). What should or can I do now??

Find a phone number for the manufacturer and call them. I would not trust anyone to lay a floor without reading the directions that come in the box.