I'm trying to set up a captive portal hotspot. This portal only provides informative content and does not allow login to authenticate. Users can only use whatsapp chat

Below I describe my scenario:

.hotspot in a RB951ui 2HnD
.captive portal with no way to authenticate
.bypass whatsapp in walled garden

Everything works fine, users can send txt, audio and img( not calls or videoconfs) and internet is blocked.
My problem is that I do not know how to disconnect users every 10 minutes of hotspot use and avoid them to being able to log in for 6 hours