What are the steps you need to follow to integrate Gravity Forms or Formidable PRO?
1)Please remove [dvin-wcql-listing] shortcode in "Request For Quote" Page.
2) Must add [dvin-wcql-listing] shortcode as one of the HTML elements where you want to show the listing.
3)Must add hidden field name of "quotelisttable" with value of "[quotelisttable]" shortcode as one of the HTML elements in Gravity Form.
Please refer to documentation(link in your plgin settings paage) for detailed explaination and screenshots.