The card does not say how often the clay can be used and does not mention combination skin: it describes the product as a care product for oily skin that helps remove excess sebum and dead cells. The method of use is given on the packaging. The claim that with regular use the skin looks more even and firm has no confirmation.
General information (not a manufacturer's instruction): if the skin feels dry or tight, it is better to use the clay less often; stop using it if irritation appears.