Please need help with online zoom meeting

Dear everyone,

recently I had some issues with our zoom meetings. we are a yoga studio in berlin and we use zoom for our online classes. Recently I had the information from different teachers, that there were people regesitered for the class, but once the opened the zoom link, there was nobody.  We use for every class a different zoom link, i checked them and it looks everything fine. 
How can I solve this problem?! we please need an urgent solution !

thank you in advance, 

Veronica