Good evening Karen and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
We are sorry to hear about the + sign not displaying properly.
I would love to help you with this topic.
I believe this is based on the rules of your Avada theme.
So you might want to reach to them for a proper solution.
In the meantime, try adding the following CSS rule to your style.css file or in your Custom CSS metabox:
.tribe-events-tickets .quantity {
height: auto !important;
}
This will not always be pretty (depending on your screen resolution – but can be tweaked with CSS).
But at least, the buttons will always display.
Let me know if that helps.
Have a great day!
Geoff B.