Is it a collective decision that you must make with your client or can you do this independently? If it's a collective decision, I would very professionally pull together a list of the facts and where PR firm has failed and present it to the client with your reasons for wanting to hire another and better PR firm, along with a few potential prospects. Most importantly backing up with the facts how this PR firm is not representing the business properly and is costing the firm more time and resources. You are a precious resource/partner, after all, and it's costing you additional time. Also, as a sidenote, I've NEVER heard of a press release going live without a link to the website. What's the point of a press release then? Unheard of!