Webinar API Question - filter results

Webinar API Question - filter results

Hi,

I am trying to get a list of upcoming webinars through the API and I can't see to find any proper documentation about this process.

I am able to get the webinar list but only the last 20 webinars. I need to get more than that and the documentation page is not helpful enough. 
https://www.zoho.com/meeting/api-integration/webinar-api/list-of-webinar-api.html

The request is done here https://meeting.zoho.com/api/v2/[ZSOID]/webinar.json?listtype=all with proper authentication so I get results, but I cannot seems to filter them.

The doc page does not even state the listtype param and that seems to be mandatory.
listtype=past and listtype=all work. Is there a way to get only the upcoming webinars (listtype=upcoming does NOT work - returns an empty collection) ?

Also, how can I get the second page of results so that I can iterate through all the results? page=2 does not work.
Is there a list of params and accepted values that this API call accepts?

Any help would be immensely appreciated!
Dan