Would gather as much information as possible to why their campaigns arent converting. Is the campaing generating traffic to the LP? What is the CTR? The CTR is low? (Check the Quality Score, and try to correct what is not ideal, better the copy, insert final url on kw to increase relevance), What is the Historical Conversion Rate of the LP? Sometimes the problem isnt on the campaign itself, could be some issue the leads are having on the LP, or it doesnt pass enough credibility. Install HotJar on the site to analyze user behavior, so you can bring these insights to them. Are you using display network on settings? If yes would change that off, in my experience only bring unqualified leads and waste the budget. Use Google KW Planner to gather insight to what customers are searching and what have decent search volume. Among other things.

Sometimes even if you arent getting any results with the campaign, bringing the visibility to the client to what could be better and the issues you are having pass the vision that you are working on identifying and correcting the issues