If you have participants in your data who don't match the demographics you ask for. Firstly, please confirm that the prescreening data provided by participants does not match the screeners you applied. You can do that by "Exporting data".
If the participants' data from the export matches the screener but they have given you contradictory answers in your survey please get in touch with them to ask which response is correct and if necessary update their information within Prolific. If the answers they have given to Prolific or you are not truthful this is valid grounds to reject the submission and if necessary report them to us.
Note that if your survey software supports it, you could redirect participants who provide inconsistent screening responses to a separate end of survey message, which asks them to return their submissions. Please refer to our Integration Guides to find out how to do this on your preferred survey software.