Depending on the originator of the calls to CPS, it is possible you may have a claim for intentional interference with the parent child relationship. There may also be a civil malicious prosecution claim. These claims can be rather arduos and would be filed in the civil trial courts as opposed the family courts. I would be happy to offer a consultation.
Talk to the case supervisor. He or she can tell if all of the calls are coming from the same person or persons even if they can't tell you. Sometimes, if the reports are all or mostly from the same person, you may be able to get CPS to "flag" your name and review the records before they begin any new investigations. Good luck.
For educational purposes only. No attorney-client relationship was created by this communication.
CPS knows where the calls are coming from, if they are unfounded, and are the same allegation, I don't understand why they would keep investigating them. I'd pass the buck to CPS, if they continue to investigate unfounded accusations, it's a waste of their resources and they should do something about it.