Your configuration shouldn't be causing billing discrepancies like that. CBSubs itself does not trigger recurring billing. We tell Stripe to bill Y every X interval and Stripe is responsible for that billing. It then notifies CBSubs when that billing has happened and we react accordingly (e.g. renew their subscription). The question is are they actually being billed every 2 days/weeks or is this just a communication problem from Stripe. There's a big difference between the two in regards to what could be going wrong.

Calendar based recurring billing doesn't work with most payment provides, including Stripe. You need to be careful when using those billing durations for recurring payments. This is because payment provides are extremely strict on what the recurring intervals can be. In Stripe's case the maximum recurring billing cycles are as follows.

365 Days
12 Months
1 Year

How that's accomplished is up to you, but that's the limit. It has no concept of "calendar month". So you should be using 1 Month or 30 Days duration for your plans if you want monthly recurring.

When we redo all of this into token billing then literally any duration will be allowed as we'll be triggering payments from CBSubs instead of letting Stripe handle the recurring billing. For now please be mindful of payment provider limitations.

I've added a bug ticket to try and implement a fallback fix for by calendar durations as best as possible. So for example if By Calendar Month is selected will just force it into a 30 day duration.

forge.joomlapolis.com/issues/9366

That should work perfectly fine since it's really the recurring period that's an issue for payment gateways. 👍