Hi. Sorry you’re experiencing this.
I haven’t heard of a “one per day” limit. Yikes! Could you please send a screenshot where you’re seeing this?
It sounds like you understand the import limits, but to be clear the import limit is charged regardless of whether or not there are new events. In other words, if you have 1 scheduled import and you set it to import every hour, it will cost 24 imports per day, regardless of whether or not new/updated events are found.
To your issue of 1 month, that is the default. You can modify this at wp-admin > Events > Settings > Imports > “Import Limit Type” setting