Well, if you are not storing any content (be it pictures or videos) of the model then it is a false DMCA report and often it is done by competitors to get you removed from Google for certain keywords or by performers that does not understand the concept of the adult affiliate marketing and that just want to be seen elsewhere of the site they are performing on.
What you can do here is to file a counter claim (support.google.com/legal/contact/lr_counternotice?product=websearch) for this request and make sure to add that you are using the live iframes that are provided by the live cam program (mention the name) and you do not have any infringement content on your servers.