A communications device and a method therein for accessing a Resource Unit (RU) are provided. The communications device and an Access Point (AP) are operating in a wireless communications network. When wanting to start an access attempt within a time interval, the communications device selects a counter value from a first range given by zero and a first Contention-Window OFDMA (CWO) value CWO1. Further, when wanting to start an access attempt outside the time interval, the communications device selects the counter value from a second range given by zero and a second CWO value CWO2, wherein the second CWO value CWO2 is larger than the first CWO value CWO1. The communications device performs a contention procedure using the selected counter value, wherein a Resource Unit (RU) is accessed in dependence of the performed contention procedure.