Good evening Matthew and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
We are sorry to hear about the message you have received. Our apologies.
I would love to help you with this topic.
These messages can show up when there is a system glitch.
The good news is that this is usually temporary.
In other words, you should now be able to download your plugins by going to https://theeventscalendar.com/my-account/downloads/
In fact, it looks like you already did.
Can you confirm ?
Best regards,
Geoff B.