Auto removal and scheduled meetings

Hi, 

We run course throughout the year and use Zoom as part of the blended learning. As such I can create a Zoom meeting which can be a year in advanced as some of our speakers have dual role as doctors in hospitals as well as teachers for us. 

I have found that meetings I have created last year are now longer available and when I try to open the Zoom meeting it comes up with invalid meeting number. 

When I check my account the meeting is no longer there and not in deleted meetings either. 

I have checked the setting and I can't see anything that would deleted them. These meetings have not been opened or used, only created for future use. 

Can any help me sort this, as it is creating double the work when I have to recreate them and resend to all our speakers. 

Thank you for your time and help with this. 

Yvonne