OK - understood. I'll investigate. Seems to work on my Android tablet and phone (you have to click the Select a Category dropdown box and select a category to open up the form for choosing duration of advert).
Two more questions - was it working on the Samsung previously?
And what happens when you click this link?
Yes was working fine last time with my android Samsung. When I click the link you provided, it opens up the advertising matrix showing the different listing options but then that closes and leaves the dropdown box and continue box but the cursor just doesn't open it again. It's just frozen - cannot open or access anything.